Sample records for kinetics laser ablation

  1. OCDR guided laser ablation device

    DOE Patents [OSTI]

    Dasilva, Luiz B. (Danville, CA); Colston, Jr., Bill W. (Livermore, CA); James, Dale L. (Tracy, CA)

    2002-01-01T23:59:59.000Z

    A guided laser ablation device. The device includes a mulitmode laser ablation fiber that is surrounded by one or more single mode optical fibers that are used to image in the vicinity of the laser ablation area to prevent tissue damage. The laser ablation device is combined with an optical coherence domain reflectometry (OCDR) unit and with a control unit which initializes the OCDR unit and a high power laser of the ablation device. Data from the OCDR unit is analyzed by the control unit and used to control the high power laser. The OCDR images up to about 3 mm ahead of the ablation surface to enable a user to see sensitive tissue such as a nerve or artery before damaging it by the laser.

  2. Multiple target laser ablation system

    DOE Patents [OSTI]

    Mashburn, Douglas N. (Knoxville, TN)

    1996-01-01T23:59:59.000Z

    A laser ablation apparatus and method are provided in which multiple targets consisting of material to be ablated are mounted on a movable support. The material transfer rate is determined for each target material, and these rates are stored in a controller. A position detector determines which target material is in a position to be ablated, and then the controller controls the beam trigger timing and energy level to achieve a desired proportion of each constituent material in the resulting film.

  3. Multiple target laser ablation system

    DOE Patents [OSTI]

    Mashburn, D.N.

    1996-01-09T23:59:59.000Z

    A laser ablation apparatus and method are provided in which multiple targets consisting of material to be ablated are mounted on a movable support. The material transfer rate is determined for each target material, and these rates are stored in a controller. A position detector determines which target material is in a position to be ablated, and then the controller controls the beam trigger timing and energy level to achieve a desired proportion of each constituent material in the resulting film. 3 figs.

  4. Laser ablation based fuel ignition

    DOE Patents [OSTI]

    Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

    1998-01-01T23:59:59.000Z

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition.

  5. Laser ablation based fuel ignition

    DOE Patents [OSTI]

    Early, J.W.; Lester, C.S.

    1998-06-23T23:59:59.000Z

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

  6. Lee, C-T A Laser Ablation Data Reduction 2006 LASER ABLATION ICP-MS: DATA

    E-Print Network [OSTI]

    Lee, Cin-Ty Aeolus

    Lee, C-T A Laser Ablation Data Reduction 2006 1 LASER ABLATION ICP-MS: DATA REDUCTION Cin-Ty A. Lee 24 September 2006 Analysis and calculation of concentrations Laser ablation analyses are done in time by turning on the laser and ablating the sample, generating a time-dependent signal (Fig. 1). Measurements

  7. Laser ablation in analytical chemistry - A review

    SciTech Connect (OSTI)

    Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

    2001-10-10T23:59:59.000Z

    Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

  8. Dual beam optical system for pulsed laser ablation film deposition

    DOE Patents [OSTI]

    Mashburn, Douglas N. (Knoxville, TN)

    1996-01-01T23:59:59.000Z

    A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary angles relative to the target surface normal, thereby generating a plume of ablated material emanating from the target.

  9. Dual beam optical system for pulsed laser ablation film deposition

    DOE Patents [OSTI]

    Mashburn, D.N.

    1996-09-24T23:59:59.000Z

    A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary angles relative to the target surface normal, thereby generating a plume of ablated material emanating from the target. 3 figs.

  10. Laser Ablation-ICP-MS Analysis of Dissected Tissue: A

    E-Print Network [OSTI]

    Hopkins, William A.

    Laser Ablation-ICP-MS Analysis of Dissected Tissue: A Conservation-Minded Approach to Assessing the animal. In this paper, we report on the application of laser ablation-ICP-MS (LA- ICP-MS) for sampling

  11. Laser ablated hard coating for microtools

    DOE Patents [OSTI]

    McLean, W. II; Balooch, M.; Siekhaus, W.J.

    1998-05-05T23:59:59.000Z

    Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10--20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode. 12 figs.

  12. Laser ablated hard coating for microtools

    DOE Patents [OSTI]

    McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Siekhaus, Wigbert J. (Berkeley, CA)

    1998-05-05T23:59:59.000Z

    Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10-20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode.

  13. Generation of Core/shell Nanoparticles with Laser Ablation 

    E-Print Network [OSTI]

    Jo, Young Kyong

    2012-10-19T23:59:59.000Z

    Two types of core/shell nanoparticles (CS-NPs) generation based on laser ablation are developed in this study, namely, double pulse laser ablation and laser ablation in colloidal solutions. In addition to the study of the generation mechanism of CS...

  14. Generation of Core/shell Nanoparticles with Laser Ablation

    E-Print Network [OSTI]

    Jo, Young Kyong

    2012-10-19T23:59:59.000Z

    Two types of core/shell nanoparticles (CS-NPs) generation based on laser ablation are developed in this study, namely, double pulse laser ablation and laser ablation in colloidal solutions. In addition to the study of the generation mechanism of CS...

  15. Innovative Laser Ablation Technology for Surface Decontamination

    SciTech Connect (OSTI)

    Chen, Winston C. H.

    2003-06-01T23:59:59.000Z

    The objective of this project is to develop a novel laser ablation in liquid for surface decontamination. It aims to achieve more efficient surface decontamination without secondary contamination. Another aim is to make this surface decontamination technology becomes economically feasible for large scale decontamination.

  16. Fast diagnostics of laser ablation used for pulsed laser deposition

    SciTech Connect (OSTI)

    Geohegan, D B

    1993-02-01T23:59:59.000Z

    The mechanisms of the laser ablation process for pulsed laser deposition thin film growth will be discussed by describing results from several implementable in situ diagnostic techniques, including gated ICCD photography, optical emission and absorption spectroscopy, ion probes and gate photon counting.

  17. Simulation of Double-Pulse Laser Ablation

    SciTech Connect (OSTI)

    Povarnitsyn, Mikhail E.; Khishchenko, Konstantin V.; Levashov, Pavel R. [Joint Institute for High Temperatures of RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Itina, Tatian E. [Laboratoire Hubert Curien, UMR CNRS 5516, 18 rue Benoit Lauras, Bat. F, 42000, St-Etienne (France)

    2010-10-08T23:59:59.000Z

    We investigate the physical reasons of a strange decrease in the ablation depth observed in femtosecond double-pulse experiments with increasing delay between the pulses. Two ultrashort pulses of the same energy produce the crater which is less than that created by a single pulse. Hydrodynamic simulation shows that the ablation mechanism is suppressed when the delay between the pulses exceeds the electron-ion relaxation time. In this case, the interaction of the second laser pulse with the expanding target material leads to the formation of the second shock wave suppressing the rarefaction wave created by the first pulse. The modeling of the double-pulse ablation for different delays between pulses confirms this explanation.

  18. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

    2014-12-02T23:59:59.000Z

    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  19. Numerical simulation of copper ablation by ultrashort laser pulses

    E-Print Network [OSTI]

    Ding, PengJi; Li, YuHong

    2011-01-01T23:59:59.000Z

    Using a modified self-consistent one-dimensional hydrodynamic lagrangian fluid code, laser ablation of solid copper by ultrashort laser pulses in vacuum was simulated to study fundamental mechanisms and to provide a guide for drilling periodic microholes or microgratings on the metal surface. The simulated laser ablation threshold is a approximate constancy in femtosecond regime and increases as the square root of pulse duration in picosecond regime. The ablation depth as a function of pulse duration shows four different regimes and a minimum for a pulse duration of ~ 12ps for various laser fluences. The influence of laser-induced plasma shielding on ablation depth is also studied.

  20. Particle analysis using laser ablation mass spectroscopy

    DOE Patents [OSTI]

    Parker, Eric P.; Rosenthal, Stephen E.; Trahan, Michael W.; Wagner, John S.

    2003-09-09T23:59:59.000Z

    The present invention provides a method of quickly identifying bioaerosols by class, even if the subject bioaerosol has not been previously encountered. The method begins by collecting laser ablation mass spectra from known particles. The spectra are correlated with the known particles, including the species of particle and the classification (e.g., bacteria). The spectra can then be used to train a neural network, for example using genetic algorithm-based training, to recognize each spectra and to recognize characteristics of the classifications. The spectra can also be used in a multivariate patch algorithm. Laser ablation mass specta from unknown particles can be presented as inputs to the trained neural net for identification as to classification. The description below first describes suitable intelligent algorithms and multivariate patch algorithms, then presents an example of the present invention including results.

  1. Solar cell contact formation using laser ablation

    DOE Patents [OSTI]

    Harley, Gabriel; Smith, David D.; Cousins, Peter John

    2014-07-22T23:59:59.000Z

    The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline materiat layer; and forming conductive contacts in the plurality of contact holes.

  2. Solar cell contact formation using laser ablation

    DOE Patents [OSTI]

    Harley, Gabriel; Smith, David; Cousins, Peter

    2012-12-04T23:59:59.000Z

    The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline material layer; and forming conductive contacts in the plurality of contact holes.

  3. Femtosecond ultraviolet laser ablation of silver and comparison with nanosecond ablation

    SciTech Connect (OSTI)

    Toftmann, B.; Schou, J. [DTU Fotonik, Riso Campus, DK-4000 Roskilde (Denmark); Doggett, B.; Budtz-Jorgensen, C.; Lunney, J. G. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2013-02-28T23:59:59.000Z

    The ablation plume dynamics arising from ablation of silver with a 500 fs, 248 nm laser at {approx}2 J cm{sup -2} has been studied using angle-resolved Langmuir ion probe and thin film deposition techniques. For the same laser fluence, the time-of-flight ion signals from femtosecond and nanosecond laser ablation are similar; both show a singly peaked time-of-flight distribution. The angular distribution of ion emission and the deposition are well described by the adiabatic and isentropic model of plume expansion, though distributions for femtosecond ablation are significantly narrower. In this laser fluence regime, the energy efficiency of mass ablation is higher for femtosecond pulses than for nanosecond pulses, but the ion production efficiency is lower.

  4. Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics

    E-Print Network [OSTI]

    Mazur, Eric

    Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics A thesis presented Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics Eric Mazur Brian R. Tull Abstract irradiated surface layer to the grain boundaries. #12;iv Lastly, we measure the photovoltaic properties

  5. Laser ablation loading of a surface-electrode ion trap

    E-Print Network [OSTI]

    David R. Leibrandt; Robert J. Clark; Jaroslaw Labaziewicz; Paul Antohi; Waseem Bakr; Kenneth R. Brown; Isaac L. Chuang

    2007-06-22T23:59:59.000Z

    We demonstrate loading by laser ablation of $^{88}$Sr$^+$ ions into a mm-scale surface-electrode ion trap. The laser used for ablation is a pulsed, frequency-tripled Nd:YAG with pulse energies of 1-10 mJ and durations of 3-5 ns. An additional laser is not required to photoionize the ablated material. The efficiency and lifetime of several candidate materials for the laser ablation target are characterized by measuring the trapped ion fluorescence signal for a number of consecutive loads. Additionally, laser ablation is used to load traps with a trap depth (40 meV) below where electron impact ionization loading is typically successful ($\\gtrsim$ 500 meV).

  6. Femtosecond laser ablation of brass in air and liquid media

    SciTech Connect (OSTI)

    Shaheen, M. E. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J. E.; Fryer, B. J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

    2013-06-07T23:59:59.000Z

    Laser ablation of brass in air, water, and ethanol was investigated using a femtosecond laser system operating at a wavelength of 785 nm and a pulse width less than 130 fs. Scanning electron and optical microscopy were used to study the efficiency and quality of laser ablation in the three ablation media at two different ablation modes. With a liquid layer thickness of 3 mm above the target, ablation rate was found to be higher in water and ethanol than in air. Ablation under water and ethanol showed cleaner surfaces and less debris re-deposition compared to ablation in air. In addition to spherical particles that are normally formed from re-solidified molten material, micro-scale particles with varying morphologies were observed scattered in the ablated structures (craters and grooves) when ablation was conducted under water. The presence of such particles indicates the presence of a non-thermal ablation mechanism that becomes more apparent when ablation is conducted under water.

  7. Plume collimation for laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Stolee, Jessica A.

    2014-09-09T23:59:59.000Z

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  8. Revisiting the interplay between ablation, collisional, and radiative processes during ns-laser ablation

    SciTech Connect (OSTI)

    Autrique, D. [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany) [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany); Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium); Gornushkin, I. [Federal Institute for Materials Research and Testing - BAM, 12489 Berlin (Germany)] [Federal Institute for Materials Research and Testing - BAM, 12489 Berlin (Germany); Alexiades, V. [Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996-1320 (United States)] [Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996-1320 (United States); Chen, Z.; Bogaerts, A. [Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium)] [Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium); Rethfeld, B. [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany)] [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany)

    2013-10-21T23:59:59.000Z

    A study of ns-laser ablation is presented, which focuses on the transient behavior of the physical processes that act in and above a copper sample. A dimensionless multiphase collisional radiative model describes the interplay between the ablation, collisional, and radiative mechanisms. Calculations are done for a 6 ns-Nd:YAG laser pulse operating at 532 nm and fluences up to 15 J/cm{sup 2}. Temporal intensity profiles as well as transmissivities are in good agreement with experimental results. It is found that volumetric ablation mechanisms and photo-processes both play an essential role in the onset of ns-laser induced breakdown.

  9. Plume dynamics in femtosecond laser ablation of metals

    SciTech Connect (OSTI)

    Donnelly, T.; Lunney, J. G. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Amoruso, S.; Bruzzese, R.; Wang, X. [Coherentia CNR-INFM and Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Fedrico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126, Napoli (Italy)

    2010-10-08T23:59:59.000Z

    In femtosecond laser ablation the plume has two components: a faster-moving plasma part and a slower nanoparticle plume which contains most of the ablated material. This paper describes the results of experiments to comprehensively characterize the plume in laser ablation of Ni with {approx_equal}300 fs pulses at 527 nm. Both single-pulse and double-pulse irradiation was used. The laser ablation depth was measured using white light interferometry. The dynamics of the plasma part of the ablation plume was measured using Langmuir ion probes. The shape of the overall ablation plume was recorded by depositing a thin film on a transparent substrate and measuring the thickness distribution. The expansion of the plasma plume is well described by the Anismov isentropic model of plume expansion. Just above the ablation threshold, the nanoparticle plume is also well described by the Anisimov expansion model. However, at higher fluence a wider plume is formed, perhaps due to the pressure exerted by plasma. For double-pulse ablation it is observed that as the second pulse is delayed beyond {approx_equal}20 ps the ablation depth is reduced and the ion yield is increased. This behaviour is due to reheating of the nascent plasma plume produced by the first pulse. This generates a pressure pulse that acts as a tamper which impedes the fragmentation and ablation of deeper layers of material.

  10. Diagnostics and applications of ultrashort pulsed laser ablation /

    E-Print Network [OSTI]

    ultra-short and high power pulsed laser system to study laser plasma interactions has attracted people Diagnostics and applications of ultrashort pulsed laser ablation / deposition 694220044 #12 attentions. Productions of GeV monoenergetic electron beams, generations of high-efficiency soft x-ray lasers

  11. RESONANCE LASER ABLATION WITH AN OPTICAL PARAMETRIC OSCILLATOR LASER AND DETECTION BY A

    E-Print Network [OSTI]

    Michel, Robert G.

    RESONANCE LASER ABLATION WITH AN OPTICAL PARAMETRIC OSCILLATOR LASER AND DETECTION BY A MICROWAVE, University of Connecticut, 55 North Eagleville Road, Storrs, CT, 06269- 3060, U.S.A. Abstract: Laser ablation of solid samples was used for the determination of trace metals by use of either a pulsed excimer laser (20

  12. Laser ablation system, and method of decontaminating surfaces

    DOE Patents [OSTI]

    Ferguson, Russell L. (Idaho Falls, ID); Edelson, Martin C. (Ames, IA); Pang, Ho-ming (Ames, IA)

    1998-07-14T23:59:59.000Z

    A laser ablation system comprising a laser head providing a laser output; a flexible fiber optic cable optically coupled to the laser output and transmitting laser light; an output optics assembly including a nozzle through which laser light passes; an exhaust tube in communication with the nozzle; and a blower generating a vacuum on the exhaust tube. A method of decontaminating a surface comprising the following steps: providing an acousto-optic, Q-switched Nd:YAG laser light ablation system having a fiber optically coupled output optics assembly; and operating the laser light ablation system to produce an irradiance greater than 1.times.10.sup.7 W/cm.sup.2, and a pulse width between 80 and 170 ns.

  13. Laser Ablation of Aluminium: Drops and Voids Johannes Roth1

    E-Print Network [OSTI]

    Roth, Johannes

    for aluminium and a complex metallic alloy. Here we will concentrate on how drops or clusters and voids canLaser Ablation of Aluminium: Drops and Voids Johannes Roth1 , Johannes Karlin1 , Christian Ulrich2

  14. Surface Decontamination Using Laser Ablation Process - 12032

    SciTech Connect (OSTI)

    Moggia, Fabrice; Lecardonnel, Xavier; Damerval, Frederique [AREVA, Back End Business Group, Clean Up Business Unit (France)

    2012-07-01T23:59:59.000Z

    A new decontamination method has been investigated and used during two demonstration stages by the Clean-Up Business Unit of AREVA. This new method is based on the use of a Laser beam to remove the contaminants present on a base metal surface. In this paper will be presented the type of Laser used during those tests but also information regarding the efficiency obtained on non-contaminated (simulated contamination) and contaminated samples (from the CEA and La Hague facilities). Regarding the contaminated samples, in the first case, the contamination was a quite thick oxide layer. In the second case, most of the contamination was trapped in dust and thin grease layer. Some information such as scanning electron microscopy (SEM), X-Ray scattering spectroscopy and decontamination factors (DF) will be provided in this paper. Laser technology appears to be an interesting one for the future of the D and D applications. As shown in this paper, the results in terms of efficiency are really promising and in many cases, higher than those obtained with conventional techniques. One of the most important advantages is that all those results have been obtained with no generation of secondary wastes such as abrasives, chemicals, or disks... Moreover, as mentioned in introduction, the Laser ablation process can be defined as a 'dry' process. This technology does not produce any liquid waste (as it can be the case with chemical process or HP water process...). Finally, the addition of a vacuum system allows to trap the contamination onto filters and thus avoiding any dissemination in the room where the process takes place. The next step is going to be a commercial use in 2012 in one of the La Hague buildings. (authors)

  15. Laser ablation for the synthesis of carbon nanotubes

    DOE Patents [OSTI]

    Holloway, Brian C.; Eklund, Peter C.; Smith, Michael W.; Jordan, Kevin C.; Shinn, Michelle

    2010-04-06T23:59:59.000Z

    Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces an output above about 50 watts/cm2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

  16. Laser ablation for the synthesis of carbon nanotubes

    DOE Patents [OSTI]

    Holloway, Brian C; Eklund, Peter C; Smith, Michael W; Jordan, Kevin C; Shinn, Michelle

    2012-11-27T23:59:59.000Z

    Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces and output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

  17. Laser ablation of iron: A comparison between femtosecond and picosecond laser pulses

    SciTech Connect (OSTI)

    Shaheen, M. E. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J. E.; Fryer, B. J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

    2013-08-28T23:59:59.000Z

    In this study, a comparison between femtosecond (fs) and picosecond (ps) laser ablation of electrolytic iron was carried out in ambient air. Experiments were conducted using a Ti:sapphire laser that emits radiation at 785 nm and at pulse widths of 110 ps and 130 fs, before and after pulse compression, respectively. Ablation rates were calculated from the depth of craters produced by multiple laser pulses incident normally to the target surface. Optical and scanning electron microscopy showed that picosecond laser pulses create craters that are deeper than those created by the same number of femtosecond laser pulses at the same fluence. Most of the ablated material was ejected from the ablation site in the form of large particles (few microns in size) in the case of picosecond laser ablation, while small particles (few hundred nanometers) were produced in femtosecond laser ablation. Thermal effects were apparent at high fluence in both femtosecond and picosecond laser ablation, but were less prevalent at low fluence, closer to the ablation threshold of the material. The quality of craters produced by femtosecond laser ablation at low fluence is better than those created at high fluence or using picosecond laser pulses.

  18. MICROANALYSIS OF SIDEROPHILE ELEMENTS IN FREMDLINGE USING LASER ABLATION ICP-MS. A. J. Campbell

    E-Print Network [OSTI]

    Grossman, Lawrence

    MICROANALYSIS OF SIDEROPHILE ELEMENTS IN FREMDLINGE USING LASER ABLATION ICP-MS. A. J. Campbell 1@midway.uchicago.edu). Introduction: Laser ablation ICP mass spectrome- try has been used to measure distributions of the highly vein in Allende (CV3-oxidized). Experimental: The laser ablation system utilized a CETAC LSX-200 laser

  19. Ultrafast laser ablation ICP-MS: role of spot size, laser fluence, and repetition rate in signal intensity

    E-Print Network [OSTI]

    Harilal, S. S.

    Ultrafast laser ablation ICP-MS: role of spot size, laser fluence, and repetition rate in signal,a Richard E. Russob and Ahmed Hassaneina Ultrafast laser ablation inductively coupled plasma mass system. Though ultrafast laser ablation sample introduction provides better accuracy and precision

  20. Analyses of femtosecond laser ablation of Ti, Zr, Hf

    E-Print Network [OSTI]

    Grojo, D; Bruneau, S; Itina, T

    2003-01-01T23:59:59.000Z

    Femtosecond laser ablation of Ti, Zr and Hf has been investigated by means of in-situ plasma diagnostics. Fast plasma imaging with the aid of an intensified charged coupled device (ICCD) camera was used to characterise the plasma plume expansion on a nanosecond time scale. Time- and spaceresolved optical emission spectroscopy was employed to perform time-of-flight measurements of ions and neutral atoms. It is shown that two plasma components with different expansion velocities are generated by the ultra-short laser ablation process. The expansion behaviour of these two components has been analysed as a function of laser fluence and target material. The results are discussed in terms of mechanisms responsible for ultra-short laser ablation.

  1. Improved time control on Cretaceous coastal deposits: new results from Sr isotope measurements using laser ablation

    E-Print Network [OSTI]

    Gilli, Adrian

    using laser ablation Stefan Burla,1 Felix Oberli,2 Ulrich Heimhofer,3 Uwe Wiechert4 and Helmut Weissert5 that laser ablation (LA) combined with multi-collector inductively cou- pled plasma mass spectrometry (MC

  2. Nanoscale patterning of graphene through femtosecond laser ablation

    SciTech Connect (OSTI)

    Sahin, R.; Akturk, S., E-mail: selcuk.akturk@itu.edu.tr [Department of Physics, Istanbul Technical University, Maslak 34469, Istanbul (Turkey); Simsek, E. [Electrical and Computer Engineering, The George Washington University, Washington, DC 20052 (United States)

    2014-02-03T23:59:59.000Z

    We report on nanometer-scale patterning of single layer graphene on SiO{sub 2}/Si substrate through femtosecond laser ablation. The pulse fluence is adjusted around the single-pulse ablation threshold of graphene. It is shown that, even though both SiO{sub 2} and Si have more absorption in the linear regime compared to graphene, the substrate can be kept intact during the process. This is achieved by scanning the sample under laser illumination at speeds yielding a few numbers of overlapping pulses at a certain point, thereby effectively shielding the substrate. By adjusting laser fluence and translation speed, 400?nm wide ablation channels could be achieved over 100??m length. Raster scanning of the sample yields well-ordered periodic structures, provided that sufficient gap is left between channels. Nanoscale patterning of graphene without substrate damage is verified with Scanning Electron Microscope and Raman studies.

  3. Sediment profiles of less commonly determined elements measured by Laser Ablation ICP-MS

    E-Print Network [OSTI]

    Mcdonough, William F.

    Sediment profiles of less commonly determined elements measured by Laser Ablation ICP on a short list of high-abundance trace elements. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry of this investigation is to harness the analytical power of Laser Ablation ICP-MS to explore the behavior of a large

  4. Brief Communication Ultra fine carbon nitride nanocrystals synthesized by laser ablation

    E-Print Network [OSTI]

    Bristol, University of

    Brief Communication Ultra fine carbon nitride nanocrystals synthesized by laser ablation in liquid form 15 October 2006 Key words: carbon nitride, laser ablation, liquid-solid interface, nanoparticle synthesized at room tem- perature and pressure using the novel technique of pulsed laser ablation

  5. Trace contaminant determination in fish scale by laser ablation technique

    SciTech Connect (OSTI)

    Lee, I.; Coutant, C.C.; Arakawa, E.T.

    1993-06-01T23:59:59.000Z

    Laser ablation on rings of fish scale has been used to analyze the historical accumulation of polychlorinated biphenyls (PCB) in striped bass in the Watts Bar Reservoir. Rings on a fish scale grow in a pattern that forms a record of the fish`s chemical intake. In conjunction with the migration patterns of fish monitored by ecologists, relative PCB concentrations in the seasonal rings of fish scale can be used to study the PCB distribution in the reservoir. In this study, a tightly-focused laser beam from a XeCl excimer laser was used to ablate and ionize a small portion of a fish scale placed in a vacuum chamber. The ions were identified and quantified by a time-of-flight mass spectrometer. Studies of this type can provide valuable information for the Department of Energy`s (DOE) off-site clean-up efforts as well as identifying the impacts of other sources to local aquatic populations.

  6. Ultraviolet laser ablation of polycarbonate and glass in air

    SciTech Connect (OSTI)

    Bormotova, T. A.; Blumenthal, R. [Auburn University, Alabama 36849 (United States)

    2009-02-01T23:59:59.000Z

    The fundamental physical processes that follow ultraviolet laser ablation of polycarbonate and borosilicate glass in air have been investigated using photodeflection as a function of the distance from the surface to probe laser. Four features were observed in the data sets for each material. Two of these features correlate well with gas dynamical predictions for the expansion of the shock wave and gas plume. The third feature is consistent with the propagation of the popping sound of the laser ablation event. The final feature, which occurs at very early times and does not shift significantly in time as the surface to probe distance is increased from 0 to greater than 6 mm, has been tentatively ascribed to the ejection of fast electrons. The final significant observation is complete blocking of the probe laser, only observed during borosilicate ablation, which is attributed to scattering of the probe laser light by macroscopic SiO{sub x} particles that grow in the final stages of plume expansion and cooling.

  7. Pico- and nanosecond laser ablation of mixed tungsten / aluminium films

    E-Print Network [OSTI]

    Wisse, M; Steiner, R; Mathys, D; Stumpp, A; Joanny, M; Travere, J M; Meyer, E

    2014-01-01T23:59:59.000Z

    In order to extend the investigation of laser-assisted cleaning of ITER-relevant first mirror materials to the picosecond regime, a commercial laser system delivering 10 picosecond pulses at 355 nm at a frequency of up to 1 MHz has been used to investigate the ablation of mixed aluminium (oxide) / tungsten (oxide) layers deposited on poly- and nanocrystalline molybdenum as well as nanocrystalline rhodium mirrors. Characterization before and after cleaning using scanning electron microscopy (SEM) and spectrophotometry shows heavy dust formation, resulting in a degradation of the reflectivity. Cleaning using a 5 nanosecond pulses at 350 and 532 nm, on the other hand, proved very promising. The structure of the film remnants suggests that in this case buckling was the underlying removal mechanism rather than ablation. Repeated coating and cleaning using nanosecond pulses is demonstrated.

  8. Pre-ignition laser ablation of nanocomposite energetic materials

    SciTech Connect (OSTI)

    Stacy, S. C.; Massad, R. A.; Pantoya, M. L. [Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)] [Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

    2013-06-07T23:59:59.000Z

    Laser ignition of energetic material composites was studied for initiation with heating rates from 9.5 Multiplication-Sign 10{sup 4} to 1.7 Multiplication-Sign 10{sup 7} K/s. This is a unique heating rate regime for laser ignition studies because most studies employ either continuous wave CO{sub 2} lasers to provide thermal ignition or pulsed Nd:YAG lasers to provide shock ignition. In this study, aluminum (Al) and molybdenum trioxide (MoO{sub 3}) nanoparticle powders were pressed into consolidated pellets and ignited using a Nd:YAG laser (1064 nm wavelength) with varied pulse energy. Results show reduced ignition delay times corresponding to laser powers at the ablation threshold for the sample. Heating rate and absorption coefficient were determined from an axisymmetric heat transfer model. The model estimates absorption coefficients from 0.1 to 0.15 for consolidated pellets of Al + MoO{sub 3} at 1064 nm wavelength. Ablation resulted from fracturing caused by a rapid increase in thermal stress and slowed ignition of the pellet.

  9. Microfluidic cell counter with embedded optical fibers fabricated by femtosecond laser ablation

    E-Print Network [OSTI]

    . Scott, and J. R. Mabesa, Jr., "Manufacturing by laser direct-write of three-dimensional devicesMicrofluidic cell counter with embedded optical fibers fabricated by femtosecond laser ablation using femtosecond laser ablation and anodic bonding. In a first application, we constructed a cell

  10. Physical mechanisms of short pulse laser ablation D. von der Linde and K. Sokolowski-Tinten

    E-Print Network [OSTI]

    von der Linde, D.

    Physical mechanisms of short pulse laser ablation D. von der Linde and K. Sokolowski precision can be obtained with the use of very short laser pulses1 . However, a convincing explanation mechanisms of short pulse laser ablation should be of great current interest, both from the point of view

  11. Atomistic Modeling of Short Pulse Laser Ablation of Metals: Connections between Melting, Spallation, and Phase Explosion

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Atomistic Modeling of Short Pulse Laser Ablation of Metals: Connections between Melting, Spallation 14, 2009; ReVised Manuscript ReceiVed: May 4, 2009 The mechanisms of short pulse laser interactions. Introduction Short pulse laser ablation is the phenomenon that is actively usedinabroadrangeofapplications

  12. Laser AblationICPMS in the Earth Sciences CURRENT PRACTICES AND OUTSTANDING ISSUES

    E-Print Network [OSTI]

    Bodnar, Robert J.

    #12;Laser Ablation­ICP­MS in the Earth Sciences CURRENT PRACTICES AND OUTSTANDING ISSUES recently been developed to facilitate the reduction of data from laser ablation inductively coupled plasma.R. MUTCHLER, L. FEDELE & R.J. BODNAR 318 APPENDIX A5: ANALYSIS MANAGEMENT SYSTEM (AMS) FOR REDUCTION OF LASER

  13. Metal ablation by picosecond laser pulses: A hybrid simulation Carsten Schafer and Herbert M. Urbassek*

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    applications, such as in laser modification of surfaces drilling, cutting, surface patterning .1 The emittedMetal ablation by picosecond laser pulses: A hybrid simulation Carsten Scha¨fer and Herbert M 2002; published 5 September 2002 We investigate picosecond laser ablation of metals using a hybrid

  14. Mechanisms of small clusters production by short and ultra-short laser ablation

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Mechanisms of small clusters production by short and ultra-short laser ablation Tatiana E. Itina a Lasers, Plasmas et Proce´de´s Photoniques (LP3 UMR 6182 CNRS), Faculte´ des Sciences de Luminy, Case 917 The mechanisms involved into the formation of clusters by pulsed laser ablation are studied both numerically

  15. Laser-ablation split-stream ICP petrochronology Andrew R.C. Kylander-Clark , Bradley R. Hacker, John M. Cottle

    E-Print Network [OSTI]

    Hacker, Bradley R.

    Laser-ablation split-stream ICP petrochronology Andrew R.C. Kylander-Clark , Bradley R. Hacker Keywords: Laser ablation Geochronology Geochemistry Accessory minerals Laser-ablation split-stream (LASS

  16. Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry

    SciTech Connect (OSTI)

    Vertes, Akos; Nemes, Peter

    2012-10-30T23:59:59.000Z

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  17. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, In vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

    2011-11-29T23:59:59.000Z

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation (LA) with electrospray ionization (ESI).

  18. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2014-08-19T23:59:59.000Z

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  19. Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2013-07-16T23:59:59.000Z

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  20. Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

    2011-06-21T23:59:59.000Z

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  1. Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry

    DOE Patents [OSTI]

    Vertes, Akos; Nemes, Peter

    2013-07-16T23:59:59.000Z

    The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

  2. Femtosecond Laser Ablation: Fundamentals and Applications

    E-Print Network [OSTI]

    Harilal, S. S.

    of femtosecond laser pulse is shorter than electron-to-ion energy transfer time and heat conduction time duration, energy, and wavelength, along with the target properties and surrounding S. S. Harilal (&) Á J. Rth anniversary of LIBS was celebrated during the LIBS 2012 conference held in Luxor, Egypt

  3. A study of particle generation during laser ablation withapplications

    SciTech Connect (OSTI)

    Liu, Chunyi

    2005-08-12T23:59:59.000Z

    A study has been made of the generation of particles during laser ablation and has included size distribution measurements and observation of the formation processes. The particle size distribution with respect to different laser parameters was obtained in-line using a differential mobility analyzer (DMA) and a particle counter. The experimental results show that the particle size varies with laser energy, laser pulsewidth, ambient gas flow rate and sample properties. The results serve as a basis for controlling the size of nanoparticles generated by laser ablation. Laser shadowgraph imaging was used to study mass ejection processes and mechanisms. At higher laser irradiance, some particles were ejected in the liquid and even in the solid phase. Time-resolved images show the propagation of the shockwaves: external shockwaves propagate outward and decelerate, and internal shockwaves reflect back and forth between the gas contact surface and the sample surface. The internal shockwave is proposed to cause the ejection of liquid particles when the internal shockwave strikes the liquid molten layer. A simulation based on vapor plume expansion was carried out and provides satisfactory agreement with experimental results. Different material properties result in different particle ejection behavior:particle ejection for most materials including metals result in a conically shaped envelope for the ejected material while ejection for silicon resembles a liquid jet. The difference in density change when the materials melt was proposed to be an important factor in the different ejection behavior. The characteristics of particles generated by laser ablation have a strong influence on the chemical analysis of the irradiated sample. Large particles are more difficult to completely vaporize and ionize, and induced preferential vaporization causes fractionation (i.e. a detected chemical composition that differs from the sample material). Large particles also result in spikes in measurements using inductively coupled plasma mass spectrometry (ICP-MS) which result in errors. Three different methods were employed to study the effects of particle size on chemical analysis: generating smaller particles utilizing a fs laser, filtering out larger particles with a cascade impactor and altering the size distribution by using a second pulse to fracture particles generated from the first pulse. It was found that the chemical composition of the particles varies with particle size. The variation of the composition with respect to particle size was analyzed and it was proposed that it was related to the vapor formed particles condensing on larger ejected liquid droplets.

  4. Testing of concrete by laser ablation

    DOE Patents [OSTI]

    Flesher, Dann J. (Benton City, WA); Becker, David L. (Kennewick, WA); Beem, William L. (Kennewick, WA); Berry, Tommy C. (Kennewick, WA); Cannon, N. Scott (Kennewick, WA)

    1997-01-01T23:59:59.000Z

    A method of testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed.

  5. Testing of concrete by laser ablation

    DOE Patents [OSTI]

    Flesher, D.J.; Becker, D.L.; Beem, W.L.; Berry, T.C.; Cannon, N.S.

    1997-01-07T23:59:59.000Z

    A method is disclosed for testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed. 1 fig.

  6. Laser ablative synthesis of carbon nanotubes

    DOE Patents [OSTI]

    Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA); Park, Cheol (Yorktown, VA)

    2010-03-02T23:59:59.000Z

    An improved method for the production of single walled carbon nanotubes that utilizes an RF-induction heated side-pumped synthesis chamber for the production of such. Such a method, while capable of producing large volumes of carbon nanotubes, concurrently permits the use of a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization. The method of the present invention utilizes a free electron laser operating at high average and peak fluence to illuminate a rotating and translating graphite/catalyst target to obtain high yields of SWNTs without the use of a vacuum chamber.

  7. Comparison of Solution-Based versus Laser Ablation Inductively Coupled Plasma Mass Spectrometry for Analysis of Larval Fish

    E-Print Network [OSTI]

    Comparison of Solution-Based versus Laser Ablation Inductively Coupled Plasma Mass Spectrometry otoliths of larvae. Herein, we evaluate the abilities of solution-based (SO) and laser ablation (LA

  8. U and Th zonation in apatite observed by laser ablation ICPMS, and implications for the (UTh)/He system

    E-Print Network [OSTI]

    Shuster, David L.

    U and Th zonation in apatite observed by laser ablation ICPMS, and implications for the (U A laser-ablation inductively-coupled plasma mass spectrometry technique was developed to measure U, Th

  9. Multidiagnostic analysis of ultrafast laser ablation of metals with pulse pair irradiation

    SciTech Connect (OSTI)

    Amoruso, S.; Bruzzese, R. [Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Wang, X. [CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); O'Connell, G.; Lunney, J. G. [School of Physics, Trinity College-Dublin, Dublin 2 (Ireland)

    2010-12-01T23:59:59.000Z

    Copper targets are irradiated in the ablation regime by pairs of equal, time-delayed collinear laser pulses separated on a timescale going from {approx_equal}2 ps to {approx_equal}2 ns. The ablation plume is characterized by ion probe diagnostic, fast imaging, and temporally and spatially resolved optical emission spectroscopy. The variation in the ablation efficiency with the delay between the pulses is analyzed by measuring the ablation crater profile with a contact profilometer. The second laser pulse modifies the characteristics of the plasma plume produced by the first pulse and the ablation efficiency. The different mechanisms involved in double pulse ultrafast laser ablation are identified and discussed. The experimental findings are interpreted in the frame of a simple model of the interaction of the second pulse with the nascent ablation plume produced by the first pulse. This model yields consistent and quantitative agreement with the experimental findings predicting the observed experimental trends of the ablation depth reduction and ion yield increase with the delay between the pulses, as well as the characteristic timescale of the observed changes. The possibility of controlling the characteristics of the plumes produced during ultrafast laser ablation via an efficient coupling of the energy of the second pulse to the various ablation components produced by the first pulse is of particular interest in ultrafast pulsed laser deposition and microprobe analyses of materials.

  10. Electrical and optical properties of diamond-like carbon films deposited by pulsed laser ablation

    E-Print Network [OSTI]

    Bristol, University of

    films, which make them more useful than polycrystalline diamond films for many applications. For exampleElectrical and optical properties of diamond-like carbon films deposited by pulsed laser ablation K e i n f o Available online 11 March 2010 Keyword: Pulsed laser ablation Diamond-like carbon films

  11. Production and acceleration of ion beams by laser ablation

    SciTech Connect (OSTI)

    Velardi, L.; Siciliano, M. V.; Delle Side, D.; Nassisi, V. [Department of Physics and I.N.F.N., LEAS Laboratory, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce (Italy)

    2012-02-15T23:59:59.000Z

    In this work, we present a new pulsed laser ablation technique to obtain energetic ion beams. The accelerator we made is a compact device able to extract and accelerate the ionic components of plasma up to 160 keV per charge state. It is composed by a generating chamber containing an expansion chamber used like first electrode. Next, a second electrode connected to ground and a third electrode connected to negative voltage are used. The third electrode is used also as Faraday cup. By the analysis of the ion signals we studied the plume parameters such as TOF accelerated signals, charge state, and divergence.

  12. A low diffraction laser beam as applied to polymer ablation Xuanhui Lu,a)

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    2 laser, laser drilling I. INTRODUCTION Laser beam quality plays an important role in quality-established process and examples are found in Refs. 7 and 8. Factors of laser beams likely to affect drillingA low diffraction laser beam as applied to polymer ablation Xuanhui Lu,a) Y. Lawrence Yao

  13. Laser ablated copper plasmas in liquid and gas ambient

    SciTech Connect (OSTI)

    Kumar, Bhupesh; Thareja, Raj K. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)] [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

    2013-05-15T23:59:59.000Z

    The dynamics of copper ablated plasma plumes generated using laser ablation of copper targets in both liquid (de-ionized water) and gas (air) ambients is reported. Using time and space resolved visible emission spectroscopy (450-650 nm), the plasma plumes parameters are investigated. The electron density (n{sub e}) determined using Stark broadening of the Cu I (3d{sup 10}4d{sup 1} {sup 2}D{sub 3/2}-3d{sup 10}4p{sup 1} {sup 2}P{sub 3/2} at 521.8 nm) line is estimated and compared for both plasma plumes. The electron temperature (T{sub e}) was estimated using the relative line emission intensities of the neutral copper transitions. Field emission scanning electron microscopy and energy dispersive x-ray spectral analysis of the ablated copper surface indicated abundance of spherical nanoparticles in liquid while those in air are amalgamates of irregular shapes. The nanoparticles suspended in the confining liquid form aggregates and exhibit a surface plasmon resonance at ?590 nm.

  14. Process and structures for fabrication of solar cells with laser ablation steps to form contact holes

    DOE Patents [OSTI]

    Harley, Gabriel; Smith, David D; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

    2013-11-19T23:59:59.000Z

    Contact holes of solar cells are formed by laser ablation to accomodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thickness.

  15. Ablation experiment and threshold calculation of titanium alloy irradiated by ultra-fast pulse laser

    SciTech Connect (OSTI)

    Zheng, Buxiang; Jiang, Gedong; Wang, Wenjun, E-mail: wenjunwang@mail.xjtu.edu.cn; Wang, Kedian; Mei, Xuesong [School of Mechanical Engineering, Xi'an Jiaotong University, No. 28, Xianning Westroad, Xi'an 710049 (China) [School of Mechanical Engineering, Xi'an Jiaotong University, No. 28, Xianning Westroad, Xi'an 710049 (China); State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710054 (China)

    2014-03-15T23:59:59.000Z

    The interaction between an ultra-fast pulse laser and a material's surface has become a research hotspot in recent years. Micromachining of titanium alloy with an ultra-fast pulse laser is a very important research direction, and it has very important theoretical significance and application value in investigating the ablation threshold of titanium alloy irradiated by ultra-fast pulse lasers. Irradiated by a picosecond pulse laser with wavelengths of 1064 nm and 532 nm, the surface morphology and feature sizes, including ablation crater width (i.e. diameter), ablation depth, ablation area, ablation volume, single pulse ablation rate, and so forth, of the titanium alloy were studied, and their ablation distributions were obtained. The experimental results show that titanium alloy irradiated by a picosecond pulse infrared laser with a 1064 nm wavelength has better ablation morphology than that of the green picosecond pulse laser with a 532 nm wavelength. The feature sizes are approximately linearly dependent on the laser pulse energy density at low energy density and the monotonic increase in laser pulse energy density. With the increase in energy density, the ablation feature sizes are increased. The rate of increase in the feature sizes slows down gradually once the energy density reaches a certain value, and gradually saturated trends occur at a relatively high energy density. Based on the linear relation between the laser pulse energy density and the crater area of the titanium alloy surface, and the Gaussian distribution of the laser intensity on the cross section, the ablation threshold of titanium alloy irradiated by an ultra-fast pulse laser was calculated to be about 0.109 J/cm{sup 2}.

  16. Internal distribution of Li and B in serpentinites from the Feather River Ophiolite, California, based on laser ablation

    E-Print Network [OSTI]

    Lee, Cin-Ty Aeolus

    , based on laser ablation inductively coupled plasma mass spectrometry Cin-Ty Aeolus Lee, Masaru Oka Occidentale, UMR6538, CNRS, F-29238 Brest CEDEX 3, France [1] Laser ablation inductively coupled plasma mass Ophiolite, California, based on laser ablation inductively coupled plasma mass spectrometry, Geochem

  17. UV-Laser-Ablation-Combustion-GC-IRMS a tool for on-line analysis of intra-annual

    E-Print Network [OSTI]

    UV-Laser-Ablation-Combustion-GC-IRMS a tool for on-line analysis of intra-annual variation of d13C standards which are also ablated by laser shots and combusted. CO2 Standard gas is needed for mass conventional method (elemental analysis-IRMS) indicated a high level of accuracy of the Laser ablation

  18. PII S0016-7037(02)01048-7 Sr investigation of igneous apatites and carbonates using laser-ablation

    E-Print Network [OSTI]

    Long, Bernard

    using laser-ablation MC-ICP-MS MARTIN BIZZARRO,1* ANTONIO SIMONETTI,1 R. K. STEVENSON,1 and STEPHAN, Greenland, have been determined by laser-ablation multicollector inductively coupled plasma mass 50% carbonate by volume, are ideally suited for laser-ablation (LA) studies be- cause

  19. Evaluation of pneumatic nebulization and ns-laser ablation ICP-MS for bulk elemental analysis and 2-dimensional

    E-Print Network [OSTI]

    Claeys, Philippe

    Evaluation of pneumatic nebulization and ns-laser ablation ICP-MS for bulk elemental analysis and 2 nebulization and ns-laser ablation ICP-MS for bulk elemental analysis and 2-dimensional element mapping of iron 20XX DOI: 10.1039/b000000x The capabilities and limitations of nanosecond laser ablation ICP ­ mass

  20. Assessment of the precision and accuracy of laser ablation-ICPMS analyses in the Fluids Research Laboratory within the Department of

    E-Print Network [OSTI]

    Bodnar, Robert J.

    1 Assessment of the precision and accuracy of laser ablation-ICPMS analyses in the Fluids Research describes results of laser ablation ICP-MS analyses of several standards of known composition conducted (AMS) for reduction of laser ablation ICPMS data. In Laser-Ablation-ICPMS in the Earth Sciences

  1. Laser ablation of electronic materials including the effects of energy coupling and plasma interactions

    SciTech Connect (OSTI)

    Zeng, Xianzhong

    2004-12-10T23:59:59.000Z

    Many laser ablation applications such as laser drilling and micromachining generate cavity structures. The study of laser ablation inside a cavity is of both fundamental and practical significance. In this dissertation, cavities with different aspect ratios (depth/diameter) were fabricated in fused silica by laser micromachining. Pulsed laser ablation in the cavities was studied and compared with laser ablation on a flat surface. The formation of laser-induced plasmas in the cavities and the effects of the cavities on the ablation processes were investigated. The temperatures and electron number densities of the resulting laser-induced plasmas in the cavities were determined from spectroscopic measurements. Reflection and confinement effects by the cavity walls and plasma shielding were discussed to explain the increased temperature and electron number density with respect to increasing cavity aspect ratio. The temporal variations of the plasma temperature and electron number density inside the cavity decreased more rapidly than outside the cavity. The effect of laser energy on formation of a plasma inside a cavity was also investigated. Propagation of the shock wave generated during pulsed laser ablation in cavities was measured using laser shadowgraph imaging and compared with laser ablation on a flat surface. It is found that outside the cavity, after about 30 ns the radius of the expanding shock wave was proportional to t2/5, which corresponds to a spherical blast wave. The calculated pressures and temperatures of the shocked air outside of the cavities were higher than those obtained on the flat surface. Lasers with femtosecond pulse duration are receiving much attention for direct fabrication of microstructures due to their capabilities of high-precision ablation with minimal damage to the sample. We have also performed experimental studies of pulsed femtosecond laser ablation on the flat surface of silicon samples and compared results with pulsed nanosecond laser ablation at a ultraviolet wavelength (266 nm). Crater depth measurements indicated that ablation efficiency was enhanced for UV femtosecond laser pulses. The electron number densities and temperatures of femtosecond-pulse plasmas decreased faster than nanosecond-pulse plasmas due to different energy deposition mechanisms. Plasma expansion in both the perpendicular and the lateral directions were studied.

  2. Improved model for the angular dependence of excimer laser ablation rates in polymer materials

    SciTech Connect (OSTI)

    Pedder, J. E. A.; Holmes, A. S. [Department of Electrical and Electronic Engineering, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Dyer, P. E. [Department of Physics, University of Hull, Hull HU6 7RX (United Kingdom)

    2009-10-26T23:59:59.000Z

    Measurements of the angle-dependent ablation rates of polymers that have applications in microdevice fabrication are reported. A simple model based on Beer's law, including plume absorption, is shown to give good agreement with the experimental findings for polycarbonate and SU8, ablated using the 193 and 248 nm excimer lasers, respectively. The modeling forms a useful tool for designing masks needed to fabricate complex surface relief by ablation.

  3. Application of laser ablation-ICP-mass spectrometry for 2-dimensional mapping of element distributions in a

    E-Print Network [OSTI]

    Claeys, Philippe

    Application of laser ablation-ICP-mass spectrometry for 2-dimensional mapping of element McDonald,d Scott W. Hassler,ce Philippe Claeysb and Frank Vanhaecke*a Laser ablation spherules, were acquired by LA-ICP-MS using two different ablation ­ standard (circular) and teardrop

  4. RAPID COMMUNICATION Quantifying the quality of femtosecond laser ablation of graphene

    E-Print Network [OSTI]

    Simsek, Ergun

    RAPID COMMUNICATION Quantifying the quality of femtosecond laser ablation of graphene Ramazan Sahin abla- tion quality and ablation size is experimentally studied on graphene-coated silicon Introduction Graphene micro- and nano-structures are considered potential building blocks for future opto

  5. UV and IR laser ablation for inductively coupled plasma mass spectrometry

    SciTech Connect (OSTI)

    Smith, M.R.; Koppenaal, D.W.; Farmer, O.T.

    1993-06-01T23:59:59.000Z

    Laser ablation particle plume compositions are characterized using inductively coupled plasma mass spectrometry (ICP/MS). This study evaluates the mass response characteristics peculiar to ICP/MS detection as a function of laser fluence and frequency. Evaluation of the ICP/MS mass response allows deductions to be made concerning how representative the laser ablation produced particle plume composition is relative to the targeted sample. Using a black glass standard, elemental fractionation was observed, primarily for alkalis and other volatile elements. The extent of elemental fractionation between the target sample and the sampled plume varied significantly as a function of laser fluences and IR and UV laser frequency.

  6. Glass particles produced by laser ablation for ICP-MS measurements

    E-Print Network [OSTI]

    Gonzalez, J.; Liu, C.; Wen, S.; Mao, X.; Russo, R.E.

    2008-01-01T23:59:59.000Z

    Glass particles produced by laser ablation for ICP-MS266nm) was used to generate glass particles from two sets ofWhen the current data on glass were compared with the metal

  7. Infrared nanosecond laser-metal ablation in atmosphere: Initial plasma during laser pulse and further expansion

    SciTech Connect (OSTI)

    Wu, Jian; Wei, Wenfu; Li, Xingwen; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

    2013-04-22T23:59:59.000Z

    We have investigated the dynamics of the nanosecond laser ablated plasma within and after the laser pulse irradiation using fast photography. A 1064 nm, 15 ns laser beam was focused onto a target made from various materials with an energy density in the order of J/mm{sup 2} in atmosphere. The plasma dynamics during the nanosecond laser pulse were observed, which could be divided into three stages: fast expansion, division into the primary plasma and the front plasma, and stagnation. After the laser terminated, a critical moment when the primary plasma expansion transited from the shock model to the drag model was resolved, and this phenomenon could be understood in terms of interactions between the primary and the front plasmas.

  8. PROOF COPY 019605JAP Effect of pulsing parameters on laser ablative cleaning of copper oxides

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    such as selectivity, controllabil- ity, and flexibility. Moreover, laser cleaning is easy to be automated is too low to melt the layer, the thermal stress due to the very rapid heating of laser pulsePROOF COPY 019605JAP PROOF COPY 019605JAP Effect of pulsing parameters on laser ablative cleaning

  9. Absorption coefficient of aluminum near the critical point and the consequences on high-power nanosecond laser ablation

    SciTech Connect (OSTI)

    Wu Benxin; Shin, Yung C. [Center for Laser-based Manufacturing, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2006-09-11T23:59:59.000Z

    During nanosecond laser ablation, the absorption coefficient determines the laser energy deposition in the target, the accurate knowledge of which near the material critical point is crucial for understanding the fundamental physics of high-power nanosecond laser ablation. In this letter, the absorption coefficient of aluminum near the critical point is calculated through the Drude model based on the measured electrical conductivity data, and its effect on laser ablation is investigated numerically using a heat transfer model. The result supports the experimental observations that phase explosion occurs for the ablation of aluminum by sufficiently intense laser pulses, and the model predicted phase explosion threshold is consistent with experimental measurements.

  10. Investigation of the effect of water content, thickness and optical properties on laser ablation of biological tissue

    E-Print Network [OSTI]

    Vaidyanathan, Varadarajan

    1991-01-01T23:59:59.000Z

    HEAT TRANSFER WITHIN TISSUE DENATUREAT ION, COAGULATION AND NECROSIS OF CELLS B I 0 C MEri I C AL PROPERTIES ABLATION: VAPORIZATION AND PYROLYSIS Fig. 1. Events in laser ablation of tissue A. The use of lasers in medicine Lasers are being used...

  11. Femtosecond laser ablation of dielectric materials in the optical breakdown regime: Expansion of a transparent shell

    SciTech Connect (OSTI)

    Garcia-Lechuga, M.; Siegel, J., E-mail: j.siegel@io.cfmac.csic.es; Hernandez-Rueda, J.; Solis, J. [Laser Processing Group, Instituto de Optica, Serrano 121, 28006 Madrid (Spain)

    2014-09-15T23:59:59.000Z

    Phase transition pathways of matter upon ablation with ultrashort laser pulses have been considered to be understood long-since for metals and semiconductors. We provide evidence that also certain dielectrics follow the same pathway, even at high pulse energies triggering optical breakdown. Employing femtosecond microscopy, we observe a characteristic ring pattern within the ablating region that dynamically changes for increasing time delays between pump and probe pulse. These transient Newton rings are related to optical interference of the probe beam reflected at the front surface of the ablating layer with the reflection at the interface of the non-ablating substrate. Analysis of the ring structure shows that the ablation mechanism is initiated by a rarefaction wave leading within a few tens of picoseconds to the formation of a transparent thin shell of reduced density and refractive index, featuring optically sharp interfaces. The shell expands and eventually detaches from the solid material at delays of the order of 100 ps.

  12. Dynamics of femto-and nanosecond laser ablation plumes investigated using optical emission spectroscopy

    E-Print Network [OSTI]

    Harilal, S. S.

    . Plasma formation occurs when a high powered pulsed laser is focused onto a target such that the energy, such as pulse duration, energy, and wave- length; along with the target properties and surrounding conditions,10 ion beams11 of various charge states, laser-ablation inductively coupled-plasma mass-spectrometry (LA

  13. Internal structure and expansion dynamics of laser ablation plumes into ambient gases

    E-Print Network [OSTI]

    Harilal, S. S.

    Internal structure and expansion dynamics of laser ablation plumes into ambient gases S. S. Harilal 13 December 2002 The effect of ambient gas on the expansion dynamics of the plasma generated by laser together with time resolved emission diagnostics, a triple structure of the plume was observed

  14. Laser diagnostic experiments on KrF laser ablation plasma-plume dynamics relevant to manufacturing applications

    SciTech Connect (OSTI)

    Gilgenbach, R.M.; Ching, C.H.; Lash, J.S.; Lindley, R.A. (Intense Energy Beam Interaction Laboratory, Nuclear Engineering Department, University of Michigan, Ann Arbor, Michigan 48109-2104 (United States))

    1994-05-01T23:59:59.000Z

    A brief review is given of the potential applications of laser ablation in the automotive and electronics manufacturing industries. Experiments are presented on KrF laser ablation of three materials relevant to manufacturing applications: aluminum metal vs aluminum--nitride (AlN) and alumina (Al[sub 2]O[sub 3]) ceramics. Plasma and neutral-atom diagnostic data are presented from resonant-holographic-interferometry, dye-laser-resonance-absorption photography, and HeNe laser deflection. Data show that plasma electron densities in excess of 10[sup 18] cm[sup [minus]3] exist in the ablation of AlN, with lower densities in Al and Al[sub 2]O[sub 3]. Aluminum neutral and ion expansion velocities are in the range of cm/[mu]s. Ambipolar electric fields are estimated to be 5--50 V/cm.

  15. aluminium laser ablation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    radiation, FLASH (Free-electron LASer in Hamburg) provides ultra-intense femtosecond radiation and laser optics: UV, XUV, and X-ray lasers; (140.2600) Lasers and laser optics:...

  16. Laser ablation of AlN films grown on sapphire substrate

    SciTech Connect (OSTI)

    Safadi, Mona R.; Thakur, Jagdish S.; Auner, Gregory W. [Department of Biomedical Engineering, Ligon Center of Vision, Wayne State University, Detroit, Michigan 48202 (United States); Department of Electrical and Computer Engineering, Wayne State University, Detroit, Michigan 48202 (United States); Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Ligon Center of Vision, Wayne State University, Detroit, Michigan 48202 (United States)

    2005-04-15T23:59:59.000Z

    Ablation threshold for single-crystal AlN semiconductor films grown epitaxially on sapphire substrate using indigenously built hollow cathode plasma deposition source molecular-beam epitaxy technique is investigated for a number of pulses by varying the fluence value of each pulse. Using a KrF excimer laser ({lambda}=248 nm and {tau}=25 ns) as a radiation source, we found that ablation of AlN thin films is a discontinuous process and its onset requires a minimum threshold fluence {approx_equal}1.59 J/cm{sup 2}. The ablation depth is analyzed for different numbers of pulses and for each number as a function of increasing fluence values. The results show that the ablation depth increases linearly with increasing pulse fluence. It is found that the use of a single pulse for ablation at a given value of fluence is more efficient than a large number of pulses at the same value of fluence/pulse. In addition, we investigated the lowest pulse-fluence limit that can sustain ablation on a disordered AlN film surface. We present a theoretical discussion about the laser energy absorption mechanism and also the rate of energy transfer from the conduction-band electrons to lattice phonons which can lead to the ablation of AlN film. It is found that the rate of energy transfer increases linearly with increasing temperature of the electron gas.

  17. Direct femtosecond laser ablation of copper with an optical vortex beam

    SciTech Connect (OSTI)

    Anoop, K. K.; Rubano, A.; Marrucci, L.; Bruzzese, R.; Amoruso, S., E-mail: amoruso@na.infn.it [Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Fittipaldi, R.; Vecchione, A. [CNR-SPIN, UOS Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Italy); Wang, X.; Paparo, D. [CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy)

    2014-09-21T23:59:59.000Z

    Laser surface structuring of copper is induced by laser ablation with a femtosecond optical vortex beam generated via spin-to-orbital conversion of the angular momentum of light by using a q-plate. The variation of the produced surface structures is studied as a function of the number of pulses, N, and laser fluence, F. After the first laser pulse (N?=?1), the irradiated surface presents an annular region characterized by a corrugated morphology made by a rather complex network of nanometer-scale ridges, wrinkles, pores, and cavities. Increasing the number of pulses (2?ablated area is gradually decorated by nanoparticles produced during laser ablation. At large number of pulses (200??1000) and a deep crater is formed. The nanostructure variation with the laser fluence, F, also evidences an interesting dependence, with a coarsening of the structure morphology as F increases. Our experimental findings demonstrate that direct femtosecond laser ablation with optical vortex beams produces interesting patterns not achievable by the more standard beams with a Gaussian intensity profile. They also suggest that appropriate tuning of the experimental conditions (F, N) can allow generating micro- and/or nano-structured surface for any specific application.

  18. Using a Fast-Scanning Electrical Nanoparticle Sizer to Characterize Nanoparticles from Laser Ablation

    SciTech Connect (OSTI)

    Chen, Da-Ren [ORNL; Cheng, Mengdawn [ORNL

    2007-01-01T23:59:59.000Z

    A Fast-Scanning Electrical Nanoparticle Sizer (FSENS) consisting of a Po 210 bipolar charger, a Nano-DMA, and an aerosol electrometer was used to characterize nanoparticles generated by laser ablating the surfaces of cement, chromium-embedded cement, stainless steel, and alumina samples. Different from previous studies, bimodal size distributions, with the nucleation mode having a geometric mean diameter ranging from 5.7-6.6 nm and a geometric standard deviation varying from 1.225-1.379, were observed for all the experimental runs. The curve fitting shows that the bimodal size distribution produced in the laser ablation can be best fitted by a lognormal distribution for the nucleation mode and a Rosin-Rammler distribution for the coagulation mode. At steady state the geometric mean diameter of the coagulation mode was affected by the laser wavelength and target material, but was less influenced by laser energy for a given wavelength. The total particle number concentrations of the two modes appear to be parabolic with respect to the laser fluence. At a given fluence, the stainless-steel sample produced the highest particle number concentration with 532- and 1064-nm lasers; the alumina sample produced the lowest particle number concentration with 266- and 1064-nm lasers. The chromium-embedded cement sample produced fewer particles with 532- and 1064 nm lasers than the pure cement sample. This study also demonstrated that FSENS can provide snapshots of the nanoparticle dynamics during laser ablation in cases of low laser fluence.

  19. Enhancement of muonium emission rate from silica aerogel with a laser ablated surface

    E-Print Network [OSTI]

    Beer, G A; Hirota, S; Ishida, K; Iwasaki, M; Kanda, S; Kawai, H; Kawamura, N; Kitamura, R; Lee, S; Marshall, W Lee G M; Mibe, T; Miyake, Y; Okada, S; Olchanski, K; Olin, A; Oishi, Y; Onishi, H; Otani, M; Saito, N; Shimomura, K; Strasser, P; Tabata, M; Tomono, D; Ueno, K; Yokoyama, K; Won, E

    2014-01-01T23:59:59.000Z

    Emission of muonium ($\\mu^+e^-$) atoms from a laser-processed aerogel surface into vacuum was studied for the first time. Laser ablation was used to create hole-like regions with diameter of about 270$~\\mu$m in a triangular pattern with hole separation in the range of 300--500$~\\mu$m. The emission probability for the laser-processed aerogel sample is at least eight times higher than for a uniform one.

  20. Enhancement of muonium emission rate from silica aerogel with a laser ablated surface

    E-Print Network [OSTI]

    G. A. Beer; Y. Fujiwara; S. Hirota; K. Ishida; M. Iwasaki; S. Kanda; H. Kawai; N. Kawamura; R. Kitamura; S. Lee; W. Lee G. M. Marshall; T. Mibe; Y. Miyake; S. Okada; K. Olchanski; A. Olin; Y. Oishi; H. Onishi; M. Otani; N. Saito; K. Shimomura; P. Strasser; M. Tabata; D. Tomono; K. Ueno; K. Yokoyama; E. Won

    2014-07-31T23:59:59.000Z

    Emission of muonium ($\\mu^+e^-$) atoms from a laser-processed aerogel surface into vacuum was studied for the first time. Laser ablation was used to create hole-like regions with diameter of about 270$~\\mu$m in a triangular pattern with hole separation in the range of 300--500$~\\mu$m. The emission probability for the laser-processed aerogel sample is at least eight times higher than for a uniform one.

  1. Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests --A laser ablation ICPMS

    E-Print Network [OSTI]

    sacculifer and Orbulina universa tests -- A laser ablation ICPMS microanalysis perspective Aleksey Yu March 2010 Editor: M.L. Delaney Keywords: Mg/Ca thermometry laser ablation ICPMS planktonic foraminifera laser ablation ICPMS to determine the extent of dissolution-caused changes in Mg/Ca distribution across

  2. Initial performance metrics of a new custom-designed ArF excimer LA-ICPMS system coupled to a two-volume laser-ablation cell

    E-Print Network [OSTI]

    Sheldon, Nathan D.

    -volume laser-ablation cell Wolfgang Mu¨ller,*a Michael Shelley,b Pascal Millerc and Sergey Broudec Received 9th 2008 DOI: 10.1039/b805995k A new custom-built excimer (193 nm) laser-ablation system with two-volume laser-ablation cell coupled to a quadrupole ICPMS is described, which combines rapid (

  3. Dense strongly coupled plasma in double laser pulse ablation of lithium: Experiment and simulation

    SciTech Connect (OSTI)

    Kumar, Ajai; Sivakumaran, V.; Ganesh, R.; Joshi, H. C. [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India); Ashwin, J. [Weizmann Institute of Science, Rehovot - 76100 (Israel)] [Weizmann Institute of Science, Rehovot - 76100 (Israel)

    2013-08-15T23:59:59.000Z

    In a simple method of low power nano-second double pulsed laser ablation experiment in collinear geometry, formation of high density strongly coupled plasma is demonstrated. Using time-resolved measurements of the Stark broadened line width and line intensity ratio of the emission lines, the density and temperature of the plasma were estimated respectively. In this experiment, it is shown that ions are strongly coupled (ion-ion coupling parameter comes out to be >4). For comparison, both single and double pulsed laser ablations are presented. For the estimated experimental plasma parameters, first principle Langevin dynamics simulation corroborates the existence of a strongly coupled regime.

  4. New Combined Laser Ablation Platform Determines Cell Wall Chemistry (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-09-01T23:59:59.000Z

    NREL has designed and developed a combined laser ablation/pulsed sample introduction/mass spectrometry platform that integrates pyrolysis and/or laser ablation with resonance-enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry. Using this apparatus, we can measure the cell wall chemical composition of untreated biomass materials. Understanding the chemical composition of untreated biomass is key to both the biochemical and thermochemical conversion of lignocellulosic biomass to biofuels. In the biochemical conversion process, the new technique provides a better understanding of the chemistry of lignin and will improve accessibility to plant sugars. In thermochemical conversion, the information provided by the new technique may help to reduce the formation of unwanted byproducts during gasification. NREL validated the ability of the system to detect pyrolysis products from plant materials using poplar, a potentially high-impact bioenergy feedstock. In the technique, biomass vapors are produced by laser ablation using the 3rd harmonic of an Nd:YAG laser (355 nm). The resulting vapors are entrained in a free jet expansion of helium, then skimmed and introduced into an ionization region. REMPI is used to ionize the vapors because it is highly sensitive for detecting lignin and aromatic metabolites. The laser ablation method was used to selectively volatilize specific plant tissues and detect lignin-based products from the vapors with enhanced sensitivity. This will allow the determination of lignin distribution in future biomass studies.

  5. Dynamics of the plumes produced by ultrafast laser ablation of metals

    SciTech Connect (OSTI)

    Donnelly, T.; Lunney, J. G. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Amoruso, S.; Bruzzese, R.; Wang, X. [Dipartimento di Scienze Fisiche and CNR-SPIN, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Ni, X. [Department of Electronic Engineering, Tianjin University of Technology and Education, Tianjin 300222 (China)

    2010-08-15T23:59:59.000Z

    We have analyzed ultrafast laser ablation of a metallic target (Nickel) in high vacuum addressing both expansion dynamics of the various plume components (ionic and nanoparticle) and basic properties of the ultrafast laser ablation process. While the ion temporal profile and ion angular distribution were analyzed by means of Langmuir ion probe technique, the angular distribution of the nanoparticulate component was characterized by measuring the thickness map of deposition on a transparent substrate. The amount of ablated material per pulse was found by applying scanning white light interferometry to craters produced on a stationary target. We have also compared the angular distribution of both the ionic and nanoparticle components with the Anisimov model. While the agreement for the ion angular distribution is very good at any laser fluence (from ablation threshold up to {approx_equal}1 J/cm{sup 2}), some discrepancies of nanoparticle plume angular distribution at fluencies above {approx_equal}0.4 J/cm{sup 2} are interpreted in terms of the influence of the pressure exerted by the nascent atomic plasma plume on the initial hydrodynamic evolution of the nanoparticle component. Finally, analyses of the fluence threshold and maximum ablation depth were also carried out, and compared to predictions of theoretical models. Our results indicate that the absorbed energy is spread over a length comparable with the electron diffusion depth L{sub c} ({approx_equal}30 nm) of Ni on the timescale of electron-phonon equilibration and that a logarithmic dependence is well-suited for the description of the variation in the ablation depth on laser fluence in the investigated range.

  6. Ultrashort laser ablation of bulk copper targets: Dynamics and size distribution of the generated nanoparticles

    SciTech Connect (OSTI)

    Tsakiris, N.; Gill-Comeau, M.; Lewis, L. J. [Département de Physique et Regroupement Québécois sur les Matériaux de Pointe (RQMP), Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7 (Canada); Anoop, K. K.; Ausanio, G.; Bruzzese, R.; Amoruso, S., E-mail: amoruso@na.infn.it [Dipartimento di Fisica, Università degli Studi di Napoli Federico II and CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy)

    2014-06-28T23:59:59.000Z

    We address the role of laser pulse fluence on expansion dynamics and size distribution of the nanoparticles produced by irradiating a metallic target with an ultrashort laser pulse in a vacuum, an issue for which contrasting indications are present in the literature. To this end, we have carried out a combined theoretical and experimental analysis of laser ablation of a bulk copper target with ?50 fs, 800?nm pulses, in an interval of laser fluencies going from few to several times the ablation threshold. On one side, molecular dynamics simulations, with two-temperature model, describe the decomposition of the material through the analysis of the evolution of thermodynamic trajectories in the material phase diagram, and allow estimating the size distribution of the generated nano-aggregates. On the other side, atomic force microscopy of less than one layer nanoparticles deposits on witness plates, and fast imaging of the nanoparticles broadband optical emission provide the corresponding experimental characterization. Both experimental and numerical findings agree on a size distribution characterized by a significant fraction (?90%) of small nanoparticles, and a residual part (?10%) spanning over a rather large size interval, evidencing a weak dependence of the nanoparticles sizes on the laser pulse fluence. Numerical and experimental findings show a good degree of consistency, thus suggesting that modeling can realistically support the search for experimental methods leading to an improved control over the generation of nanoparticles by ultrashort laser ablation.

  7. The effect of ultrafast laser wavelength on ablation properties and implications on sample introduction in inductively coupled plasma mass spectrometry

    SciTech Connect (OSTI)

    LaHaye, N. L.; Harilal, S. S.; Diwakar, P. K.; Hassanein, A. [Center for Materials under Extreme Environment, School of Nuclear Engineering Purdue University, West Lafayette, Indiana 47907 (United States); Kulkarni, P. [Centers for Disease Control and Prevention, National Institute of Occupational Safety and Health, Cincinnati, Ohio 45213 (United States)

    2013-07-14T23:59:59.000Z

    We investigated the role of femtosecond (fs) laser wavelength on laser ablation (LA) and its relation to laser generated aerosol counts and particle distribution, inductively coupled plasma-mass spectrometry (ICP-MS) signal intensity, detection limits, and elemental fractionation. Four different NIST standard reference materials (610, 613, 615, and 616) were ablated using 400 nm and 800 nm fs laser pulses to study the effect of wavelength on laser ablation rate, accuracy, precision, and fractionation. Our results show that the detection limits are lower for 400 nm laser excitation than 800 nm laser excitation at lower laser energies but approximately equal at higher energies. Ablation threshold was also found to be lower for 400 nm than 800 nm laser excitation. Particle size distributions are very similar for 400 nm and 800 nm wavelengths; however, they differ significantly in counts at similar laser fluence levels. This study concludes that 400 nm LA is more beneficial for sample introduction in ICP-MS, particularly when lower laser energies are to be used for ablation.

  8. Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

    SciTech Connect (OSTI)

    Nathan Joe Saetveit

    2008-08-18T23:59:59.000Z

    Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 {micro}g L{sup -1} or better were found for P, Mn, Fe, Cu, and Zn in a 60 {micro}L injection in a physiological saline matrix.

  9. Spatio-temporal mapping of ablated species in ultrafast laser-produced graphite plasmas

    SciTech Connect (OSTI)

    Al-Shboul, K. F.; Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2012-05-28T23:59:59.000Z

    We studied the spatial and temporal distributions of ionic, neutral, and molecular species generated by femtosecond laser produced plasma under varying ambient nitrogen gas pressures. Plasmas were generated by irradiating planar graphite targets using 40 fs pulses of 800 nm radiation from a Ti:Sapphire laser. The results show that in the presence of an ambient gas, the molecular species spatial extension and lifetime are directly correlated to the evolution of excited ions. The present studies also provide valuable insights into the evolution history of various species and their excitation during ultrafast laser ablation.

  10. assisted laser ablation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of producing ions from small ionization (DESI),5 desorption atmospheric pressure chemical ionization (DAPCI),6 and matrix- assisted laser Vertes, Akos 10 Numerical simulation...

  11. Safeguards Verification Measurements using Laser Ablation, Absorbance Ratio Spectrometry in Gaseous Centrifuge Enrichment Plants

    SciTech Connect (OSTI)

    Anheier, Norman C.; Cannon, Bret D.; Kulkarni, Gourihar R.; Munley, John T.; Nelson, Danny A.; Qiao, Hong (Amy) [Amy; Phillips, Jon R.

    2012-07-17T23:59:59.000Z

    Laser Ablation Absorbance Ratio Spectrometry (LAARS) is a new verification measurement technology under development at the US Department of Energy (DOE) Pacific Northwest National Laboratory (PNNL). LAARS uses three lasers to ablate and then measure the relative isotopic abundance of uranium compounds. An ablation laser is tightly focused on uranium-bearing solids, producing a small atomic uranium vapor plume. Two collinear wavelength-tuned spectrometry lasers transit through the plume and the absorbance of U-235 and U-238 isotopes are measured to determine U-235 enrichment. The measurement is independent of chemical form and degree of dilution with nuisance dust and other materials. LAARS has high relative precision and detection limits approaching the femtogram range for U-235. The sample is scanned and assayed point-by-point at rates reaching 1 million measurements/hour, enabling LAARS to detect and analyze uranium in trace samples. The spectrometer is assembled using primarily commercially available components and features a compact design and automated analysis.Two specific gaseous centrifuge enrichment plant (GCEP) applications of the spectrometer are currently under development: 1) LAARS-Environmental Sampling (ES), which collects and analyzes aerosol particles for GCEP misuse detection and 2) LAARS-Destructive Assay (DA), which enables onsite enrichment DA sample collection and analysis for protracted diversion detection. The two applications propose game-changing technological advances in GCEP safeguards verification.

  12. Transition between nonthermal and thermal ablation of metallic targets under the strike of high-fluence ultrashort laser pulses

    SciTech Connect (OSTI)

    Yang, J.; Zhao, Y.; Zhu, X. [Institute of Modern Optics, Nankai University, Key Laboratory of Opto-electronic Information Science and Technology, Education Ministry of China, Tianjin 300071 (China)

    2006-02-27T23:59:59.000Z

    The mutual transition dynamics between nonthermal and thermal dominant ablation processes is investigated in the hole-drilling and line-scribing experiments on aluminum samples with intense 50 fs to 24 ps laser pulses. It is found that a critical pulse width that separates the two different ablation regimes monotonically reduces with the increasing laser fluence. Theoretical analyses suggest that the complex interplay between photomechanical stress fragmentation and phase explosion could be responsible for these observations. A semiempirical transition law between the two ablation regimes is introduced, which is consistent with measured experimental data.

  13. Optical time of flight studies of lithium plasma in double pulse laser ablation: Evidence of inverse Bremsstrahlung absorption

    SciTech Connect (OSTI)

    Sivakumaran, V.; Joshi, H. C.; Singh, R. K.; Kumar, Ajai, E-mail: ajai@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2014-06-15T23:59:59.000Z

    The early stage of formation of lithium plasma in a collinear—double pulse laser ablation mode has been studied using optical time of flight (OTOF) spectroscopy as a function of inter-pulse delay time, the distance from the target surface and the fluence of the ablation lasers. The experimental TOF measurements were carried out for lithium neutral (670.8?nm and 610.3?nm), and ionic (548.4?nm and 478.8?nm) lines. These experimental observations have been compared with that for single pulse laser ablation mode. It is found that depending on the fluence and laser pulse shape of the first pre-ablation laser and the second main ablation laser, the plasma plume formation and its characteristic features can be described in terms of plume-plume or laser-plume interaction processes. Moreover, the enhancement in the intensity of Li neutral and ionic lines is observed when the laser-plume interaction is the dominant process. Here, we see the evidence of the role of inverse Bremsstrahlung absorption process in the initial stage of formation of lithium plasma in this case.

  14. Generation of low work function, stable compound thin films by laser ablation

    DOE Patents [OSTI]

    Dinh, Long N. (Concord, CA); McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Fehring, Jr., Edward J. (Dublin, CA); Schildbach, Marcus A. (Livermore, CA)

    2001-01-01T23:59:59.000Z

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  15. US-Guided Femoral and Sciatic Nerve Blocks for Analgesia During Endovenous Laser Ablation

    SciTech Connect (OSTI)

    Yilmaz, Saim, E-mail: ysaim@akdeniz.edu.tr; Ceken, Kagan; Alimoglu, Emel; Sindel, Timur [Akdeniz University School of Medicine, Department of Radiology (Turkey)] [Akdeniz University School of Medicine, Department of Radiology (Turkey)

    2013-02-15T23:59:59.000Z

    Endovenous laser ablation may be associated with significant pain when performed under standard local tumescent anesthesia. The purpose of this study was to investigate the efficacy of femoral and sciatic nerve blocks for analgesia during endovenous ablation in patients with lower extremity venous insufficiency. During a 28-month period, ultrasound-guided femoral or sciatic nerve blocks were performed to provide analgesia during endovenous laser ablation in 506 legs and 307 patients. The femoral block (n = 402) was performed at the level of the inguinal ligament, and the sciatic block at the posterior midthigh (n = 124), by injecting a diluted lidocaine solution under ultrasound guidance. After the blocks, endovenous laser ablations and other treatments (phlebectomy or foam sclerotherapy) were performed in the standard fashion. After the procedures, a visual analogue pain scale (1-10) was used for pain assessment. After the blocks, pain scores were 0 or 1 (no pain) in 240 legs, 2 or 3 (uncomfortable) in 225 legs, and 4 or 5 (annoying) in 41 legs. Patients never experienced any pain higher than score 5. The statistical analysis revealed no significant difference between the pain scores of the right leg versus the left leg (p = 0.321) and between the pain scores after the femoral versus sciatic block (p = 0.7). Ultrasound-guided femoral and sciatic nerve blocks may provide considerable reduction of pain during endovenous laser and other treatments, such as ambulatory phlebectomy and foam sclerotherapy. They may make these procedures more comfortable for the patient and easier for the operator.

  16. Velocity distribution measurements in atomic beams generated using laser induced back-ablation

    E-Print Network [OSTI]

    Denning, A; Lee, S; Ammonson, M; Bergeson, S D

    2008-01-01T23:59:59.000Z

    We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

  17. Ablation of solids using a femtosecond extreme ultraviolet free electron laser

    SciTech Connect (OSTI)

    Stojanovic, N.; Linde, D. von der; Sokolowski-Tinten, K.; Zastrau, U.; Perner, F.; Foerster, E.; Sobierajski, R.; Nietubyc, R.; Jurek, M.; Klinger, D.; Pelka, J.; Krzywinski, J.; Juha, L; Cihelka, J.; Velyhan, A.; Koptyaev, S.; Hajkova, V.; Chalupsky, J.; Kuba, J.; Tschentscher, T. [Institut fuer Experimentelle Physik, Universitaet Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg (Germany); Institut fuer Optik und Quantenelektronik, FSU Jena, 07743 Jena (Germany); Institute of Physics, PAS, Al. Lotnikov 32/46, 02-668 Warsaw (Poland); Institute of Physics, ASCR, 182 21 Prague (Czech Republic); Czech Technical University, 115 19 Prague (Czech Republic); Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22605 Hamburg (Germany)] (and others)

    2006-12-11T23:59:59.000Z

    The ablation of solids by high energy femtosecond pulses from an extreme ultraviolet (XUV) free electron laser has been investigated using picosecond optical imaging. The time-resolved measurements are supplemented by an analysis of the permanent structural surface modifications. Compared with femtosecond optical excitation, distinct differences in the material response are found which are attributed to the increased penetration depth of the XUV radiation and the absence of any absorption nonlinearities.

  18. arf laser ablation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    p... Tsuda, N; Tsuda, Norio; Yamada, Jun 2004-01-01 2 June 1981 Vol. 6, No. 6 OPTICS LETTERS 293 Tunable ArF* excimer-laser source Physics Websites Summary: June 1981 ...

  19. Copyright c 2002 Tech Science Press CMES, vol.3, no.5, pp.539-555, 2002 Multiscale Modeling of Laser Ablation: Applications to Nanotechnology

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    of Laser Ablation: Applications to Nanotechnology Leonid V. Zhigilei1 and Avinash M. Dongare 1 Abstract-driven methods in nanotechnology. In this pa- per we discuss two computational schemes developed for simulation, applications of laser ablation have been extended into emerging area of nanotechnology. In particular, laser

  20. Laser ablation of contaminants from concrete and metal surfaces. Topical report, June--December 1994

    SciTech Connect (OSTI)

    Freiwald, J.; Freiwald, D.A.

    1994-12-01T23:59:59.000Z

    Tests have demonstrated that it is possible to clean coatings off surfaces using high-power, pulsed, high-repetition-rate lasers. Purpose of this contract is to demonstrate (1) that pulsed-repetition lasers can be used to remove paint from concrete and metal surfaces, including cleaning out the surface pores, (2) that the cleaning process will result in negligible release of contaminated ablated material to the environment, and (3) that the process generates negligible additional waste compared to competing technologies. This report covers technical progress during Phase 1 of the contract and makes recommendations for technology development in Phase 2.

  1. Synthesis of Ag-deionized water nanofluids using multi-beam laser ablation in liquids

    SciTech Connect (OSTI)

    Tran, P.X.; Soong, Yee; Chyu, M.K.

    2007-12-01T23:59:59.000Z

    Multi-pulse laser ablation of silver in deionized water was studied. The laser beams were arranged in a cross-beam configuration. In our experiments, two single-mode, Q-switched Nd-Yag lasers operating at 1064 nm, pulse duration of 5.5 ns and 10 Hz rep rate were used. The laser fluence of the second beam was 0.265 J/cm2 for all tests. Two levels of the laser fluences were used for the ablating beam: 0.09 and 0.265 J/cm2 (11,014 and 33,042 J/cm2 at the focal point, respectively). The silver target was at 50mm from the cell window and 10mm deep. The second beam was aligned parallelly with the silver target and focused at 2mm in front of the focal point of the ablating beam. For all cases, the delay time between the ablating beam and the cross-beam was 40 ms. In general, the ablated particles were almost all spherical. For fluence of 0.09 J/cm 2 and single-beam approach, the mean particle size was about 29 nm. The majority of the particles, however, were in 19–35nm range and there were some big ones as large as 50–60nm in size. For double-beam approach, the particles were smaller with the average size of about 18nm and the majority of the particles were in 9–21nm range with few big one as large as 40 nm. For the beam fluence of 0.265 J/cm2 and single-beam configuration, the particle sizes were smaller, the mean particles size was about 18nm and the majority of the particles were in the range of 10–22nm with some big one as large as 40 nm. For double-beam approach, the mean particle size was larger (24.2 nm) and the majority of the particle were distributed from 14 to 35nm with some big particles can be found with sizes as big as 70 nm. Preliminary measurements of the thermal conductivity and viscosity of the produced samples showed that the thermal conductivity increased about 3–5% and the viscosity increased 3.7% above the base fluid viscosity even with the particle volume concentration as low as 0.01%.

  2. Investigation of the effect of water content, thickness and optical properties on laser ablation of biological tissue 

    E-Print Network [OSTI]

    Vaidyanathan, Varadarajan

    1991-01-01T23:59:59.000Z

    density of the laser beam. Polyacrylamide gel with congo-red dye and non-fat milk powder as the absorbing and scattering agents respectively was subjected to Argon laser radiation. Ablation velocity increased with increase in amount of scattering added... bleeding, by using flexible endoscopes. Due to the precise cutting features of the lasers, there is less surrounding tissue edema, inflammatory response and fibrosis [16]. Ophthalmology: Lasers are used in the treatment of eye...

  3. Optical analysis of the ablation processes in pulsed laser deposition

    E-Print Network [OSTI]

    Reilly, Anne

    spectral lines. #12;3 II. Introduction Pulsed laser deposition, or PLD, is a technique by which material be studied and controlled, a greater overall command of the deposition process could be achieved.2 to see very clear plumes, #12;4 significant blackbody emission, and evidence of spectral lines

  4. Ablation by short optical and X-ray laser pulses N.A. Inogamova, S.I. Anisimova, V.V. Zhakhovskyb,c, A.Ya. Faenovb,d, Yu.V. Petrova,

    E-Print Network [OSTI]

    Fominov, Yakov

    Ablation by short optical and X-ray laser pulses N.A. Inogamova, S.I. Anisimova, V.V. Zhakhovskyb. Keywords: Short pulse laser ablation, EUV and X-ray laser ablation of LiF, material strength defined in laser experiment 1. INTRODUCTION Short pulse OL and XRL are important for practical applications

  5. Low work function surface layers produced by laser ablation using short-wavelength photons

    DOE Patents [OSTI]

    Balooch, Mehdi (Berkeley, CA); Dinh, Long N. (Concord, CA); Siekhaus, Wigbert J. (Berkeley, CA)

    2000-01-01T23:59:59.000Z

    Short-wavelength photons are used to ablate material from a low work function target onto a suitable substrate. The short-wavelength photons are at or below visible wavelength. The elemental composition of the deposit is controlled by the composition of the target and the gaseous environment in which the ablation process is performed. The process is carried out in a deposition chamber to which a short-wavelength laser is mounted and which includes a substrate holder which can be rotated, tilted, heated, or cooled. The target material is mounted onto a holder that spins the target during laser ablation. In addition, the deposition chamber is provided with a vacuum pump, an external gas supply with atomizer and radical generator, a gas generator for producing a flow of molecules on the substrate, and a substrate cleaning device, such as an ion gun. The substrate can be rotated and tilted, for example, whereby only the tip of an emitter can be coated with a low work function material.

  6. Adjustment of ablation shapes and subwavelength ripples based on electron dynamics control by designing femtosecond laser pulse trains

    SciTech Connect (OSTI)

    Yuan Yanping; Jiang Lan; Li Xin; Wang Cong [Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Lu Yongfeng [Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 (United States)

    2012-11-15T23:59:59.000Z

    A quantum model is proposed to investigate femtosecond laser pulse trains processing of dielectrics by including the plasma model with the consideration of laser particle-wave duality. Central wavelengths (400 nm and 800 nm) strongly impact the surface plasmon field distribution, the coupling field intensity distribution (between the absorbed intensity and the surface plasma), and the distribution of transient localized free electron density in the material. This, in turn, significantly changes the localized transient optical/thermal properties during laser materials processing. The effects of central wavelengths on ablation shapes and subwavelength ripples are discussed. The simulation results show that: (1) ablation shapes and the spacing of subwavelength ripples can be adjusted by localized transient electron dynamics control using femtosecond laser pulse trains; (2) the adjustment of the radii of ablation shapes is stronger than that of the periods of subwavelength ripples.

  7. Kinetics of ion and prompt electron emission from laser-produced plasma

    SciTech Connect (OSTI)

    Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China); Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Ding, H. [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)

    2013-07-15T23:59:59.000Z

    We investigated ion emission dynamics of laser-produced plasma from several elements, comprised of metals and non-metals (C, Al, Si, Cu, Mo, Ta, W), under vacuum conditions using a Faraday cup. The estimated ion flux for various targets studied showed a decreasing tendency with increasing atomic mass. For metals, the ion flux is found to be a function of sublimation energy. A comparison of temporal ion profiles of various materials showed only high-Z elements exhibited multiple structures in the ion time of flight profile indicated by the observation of higher peak kinetic energies, which were absent for low-Z element targets. The slower ions were seen regardless of the atomic number of target material propagated with a kinetic energy of 1–5 keV, while the fast ions observed in high-Z materials possessed significantly higher energies. A systematic study of plasma properties employing fast photography, time, and space resolved optical emission spectroscopy, and electron analysis showed that there existed different mechanisms for generating ions in laser ablation plumes. The origin of high kinetic energy ions is related to prompt electron emission from high-Z targets.

  8. Novel Technique for the CO2 Laser Fabrication of Optical Devices with Sub-Micrometer Ablation Depth Precision

    E-Print Network [OSTI]

    a strong wavelength and temperature dependence 5 . In this work a 100 W, pulse width modulated (PWM), CO2Novel Technique for the CO2 Laser Fabrication of Optical Devices with Sub-Micrometer Ablation Depth techniques for the processing of fibre end face and cladding surfaces using a 9.6 µm CO2 laser. We

  9. Dynamics of femtosecond laser absorption of fused silica in the ablation regime

    SciTech Connect (OSTI)

    Lebugle, M., E-mail: lebugle@lp3.univ-mrs.fr; Sanner, N.; Varkentina, N.; Sentis, M.; Utéza, O. [Aix Marseille Université, CNRS, LP3 UMR 7341, 13288 Marseille (France)

    2014-08-14T23:59:59.000Z

    We investigate the ultrafast absorption dynamics of fused silica irradiated by a single 500?fs laser pulse in the context of micromachining applications. A 60-fs-resolution pump-probe experiment that measures the reflectivity and transmissivity of the target under excitation is developed to reveal the evolution of plasma absorption. Above the ablation threshold, an overcritical plasma with highly non-equilibrium conditions is evidenced in a thin layer at the surface. The maximum electron density is reached at a delay of 0.5?ps after the peak of the pump pulse, which is a strong indication of the occurrence of electronic avalanche. The results are further analyzed to determine the actual feedback of the evolution of the optical properties of the material on the pump pulse. We introduce an important new quantity, namely, the duration of absorption of the laser by the created plasma, corresponding to the actual timespan of laser absorption by inverse Bremsstrahlung. Our results indicate an increasing contribution of plasma absorption to the total material absorption upon raising the excitation fluence above the ablation threshold. The role of transient optical properties during the energy deposition stage is characterized and our results emphasize the necessity to take it into account for better understanding and control of femtosecond laser-dielectrics interaction.

  10. VOLUME 81, NUMBER 1 P H Y S I C A L R E V I E W L E T T E R S 6 JULY 1998 Transient States of Matter during Short Pulse Laser Ablation

    E-Print Network [OSTI]

    von der Linde, D.

    of Matter during Short Pulse Laser Ablation K. Sokolowski-Tinten, J. Bialkowski, A. Cavalleri, and D. von, Institutskii prospekt 12, Chernogolovka, Russia (Received 20 March 1998) Short pulse laser ablation duration [3]. A distinctive feature of short pulse ablation is that laser- material interaction

  11. Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma

    SciTech Connect (OSTI)

    Ikeda, Shunsuke, E-mail: shunsuke.ikeda@riken.jp; Sekine, Megumi [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan) [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Riken, Wako, Saitama (Japan); Romanelli, Mark [Cornell University, Ithaca, New York 14850 (United States)] [Cornell University, Ithaca, New York 14850 (United States); Cinquegrani, David [University of Michigan, Ann Arbor, Michigan 48109 (United States)] [University of Michigan, Ann Arbor, Michigan 48109 (United States); Kumaki, Masafumi [Waseda University, Shinjuku, Tokyo (Japan)] [Waseda University, Shinjuku, Tokyo (Japan); Fuwa, Yasuhiro [Kyoto University, Uji, Kyoto (Japan)] [Kyoto University, Uji, Kyoto (Japan); Kanesue, Takeshi; Okamura, Masahiro [Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Brookhaven National Laboratory, Upton, New York 11973 (United States); Horioka, Kazuhiko [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)] [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)

    2014-02-15T23:59:59.000Z

    A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface.

  12. The role of asymmetric excitation in self-organized nanostructure formation upon femtosecond laser ablation

    SciTech Connect (OSTI)

    Reif, Juergen; Varlamova, Olga; Varlamov, Sergej; Bestehorn, Michael [Brandenburgische Technische Universitaet (BTU) Cottbus Platz der Deutschen Einheit 1, 03046 Cottbus (Germany); Brandenburgische Technische Universitaet (BTU) Cottbus Platz der Deutschen Einheit 1, 03046 Cottbus (Germany)

    2012-07-30T23:59:59.000Z

    Surface pattering upon multi-pulse femtosecond laser ablation is modeled by a non-linear-dynamic erosion/smoothing model, similar to structure formation during ion sputtering. The model is adopted to account for the influence of laser polarization on nanostructure features. Based on a nonlinear equation of the Kuramoto-Siavshinsky type, it is shown that the directional anisotropy in the pattern formation may result from a spatial anisotropy of the initial excitation/energy-coupling process, such as resonant coupling to surface plasmons/polaritons, or electron diffusion properties. Also, anisotropy of elasto-dynamic surface and diffusion properties may be involved. A comparison of numeric simulations based on the model with corresponding experi-mental results gives a very good agreement.

  13. Safeguards Verification Measurements using Laser Ablation, Absorbance Ratio Spectrometry in Gaseous Centrifuge Enrichment Plants

    SciTech Connect (OSTI)

    Anheier, Norman C.; Cannon, Bret D.; Qiao, Hong (Amy) [Amy; Phillips, Jon R.

    2012-07-01T23:59:59.000Z

    Laser Ablation Absorbance Ratio Spectrometry (LAARS) is a new verification measurement technology under development at the US Department of Energy’s (DOE) Pacific Northwest National Laboratory (PNNL). LAARS uses three lasers to ablate and then measure the relative isotopic abundance of uranium compounds. An ablation laser is tightly focused on uranium-bearing solids producing a small plume containing uranium atoms. Two collinear wavelength-tuned spectrometry lasers transit through the plume and the absorbance of U-235 and U-238 isotopes are measured to determine U-235 enrichment. The measurement has high relative precision and detection limits approaching the femtogram range for uranium. It is independent of chemical form and degree of dilution with nuisance dust and other materials. High speed sample scanning and pinpoint characterization allow measurements on millions of particles/hour to detect and analyze the enrichment of trace uranium in samples. The spectrometer is assembled using commercially available components at comparatively low cost, and features a compact and low power design. Future designs can be engineered for reliable, autonomous deployment within an industrial plant environment. Two specific applications of the spectrometer are under development: 1) automated unattended aerosol sampling and analysis and 2) on-site small sample destructive assay measurement. The two applications propose game-changing technological advances in gaseous centrifuge enrichment plant (GCEP) safeguards verification. The aerosol measurement instrument, LAARS-environmental sampling (ES), collects aerosol particles from the plant environment in a purpose-built rotating drum impactor and then uses LAARS-ES to quickly scan the surface of the impactor to measure the enrichments of the captured particles. The current approach to plant misuse detection involves swipe sampling and offsite analysis. Though this approach is very robust it generally requires several months to obtain results from a given sample collection. The destructive assay instrument, LAARS-destructive assay (DA), uses a simple purpose-built fixture with a sampling planchet to collect adsorbed UF6 gas from a cylinder valve or from a process line tap or pigtail. A portable LAARS-DA instrument scans the microgram quantity of uranium collected on the planchet and the assay of the uranium is measured to ~0.15% relative precision. Currently, destructive assay samples for bias defect measurements are collected in small sample cylinders for offsite mass spectrometry measurement.

  14. Spatially tracking 13C labeled substrate (bicarbonate) accumulation in microbial communities using laser ablation isotope ratio mass spectrometry

    SciTech Connect (OSTI)

    Moran, James J.; Doll, Charles G.; Bernstein, Hans C.; Renslow, Ryan S.; Cory, Alexandra B.; Hutchison, Janine R.; Lindemann, Stephen R.; Fredrickson, Jim K.

    2014-08-25T23:59:59.000Z

    This is a manuscript we would like to submit for publication in Environmental Microbiology Reports. This manuscript contains a description of a laser ablation isotope ratio mass spectrometry methodology developed at PNNL and applied to a microbial system at a PNNL project location – Hot Lake, Washington. I will submit a word document containing the entire manuscript with this Erica input request form.

  15. SF2I.7.pdf CLEO:2014 2014 OSA Emission and expansion features of ns and fs laser ablation

    E-Print Network [OSTI]

    Harilal, S. S.

    of an ambient leading to further excitation of plume species as well as enhancing excited molecular species and hydrodynamic expansion dynamics of ns and fs laser ablated metal plasmas in the presence of an ambient were studied. The structure and dynamics of both ns and fs plumes obtained from optical diagnostic

  16. Structural and magnetic properties of NiZn and Zn ferrite thin films obtained by laser ablation deposition

    E-Print Network [OSTI]

    McHenry, Michael E.

    Structural and magnetic properties of NiZn and Zn ferrite thin films obtained by laser ablation ferrite structures. Our investigations were performed on NiZn and Zn ferrite films deposited on silicon of the blocking temperature in both NiZn and Zn ferrite systems. © 2005 American Institute of Physics. DOI: 10

  17. Temporal and spatial evolution of laser ablated plasma from YBa,Ch.& S. S. Harilal, P. Radhakrishnan, V. P. N. Nampoori, and C. P. G. Vallabhan

    E-Print Network [OSTI]

    Harilal, S. S.

    to local heating and drilling, the sample was rotated about an axis parallel to the laser beam. LaserTemporal and spatial evolution of laser ablated plasma from YBa,Ch.& S. S. Harilal, P. Radhakrishnan, V. P. N. Nampoori, and C. P. G. Vallabhan Laser Division, Department of Physics, Cochin

  18. Absorption of a single 500 fs laser pulse at the surface of fused silica: Energy balance and ablation efficiency

    SciTech Connect (OSTI)

    Varkentina, N.; Sanner, N.; Lebugle, M.; Sentis, M.; Utéza, O. [Aix-Marseille Université, CNRS, LP3 UMR 7341, 13288 Marseille (France)] [Aix-Marseille Université, CNRS, LP3 UMR 7341, 13288 Marseille (France)

    2013-11-07T23:59:59.000Z

    Ablation of fused silica by a single femtosecond laser pulse of 500 fs pulse duration is investigated from the perspective of efficiency of incident photons to remove matter. We measure the reflected and transmitted fractions of the incident pulse energy as a function of fluence, allowing us to recover the evolution of absorption at the material surface. At the ablation threshold fluence, 25% of incident energy is absorbed. At high fluences, this ratio saturates around 70% due to the appearance of a self-triggered plasma mirror (or shielding) effect. By using the energy balance retrieved experimentally and measurements of the ablated volume, we show that the amount of absorbed energy is far above the bonding energy of fused silica at rest and also above the energy barrier to ablate the material under non-equilibrium thermodynamic conditions. Our results emphasize the crucial role of transient plasma properties during the laser pulse and suggest that the major part of the absorbed energy has been used to heat the plasma formed at the surface of the material. A fluence range yielding an efficient and high quality ablation is also defined, which makes the results relevant for femtosecond micromachining processes.

  19. Addition and recombination reactions of unsaturated radicals using a novel laser kinetics spectrometer

    E-Print Network [OSTI]

    Ismail, Huzeifa

    2008-01-01T23:59:59.000Z

    This thesis describes the construction of a novel, low-noise laser kinetics spectrometer. A quasi-CW (picosecond pulse), tunable Ti:Sapphire laser is used to detect various transient species in laser flash photolysis ...

  20. Isotope Ratio Analysis on Micron-Sized Particles in Complex Matrices by Laser Ablation – Absorption Ratio Spectrometry

    SciTech Connect (OSTI)

    Bushaw, Bruce A.; Anheier, Norman C.

    2009-12-01T23:59:59.000Z

    Laser ablation has been combined with dual tunable diode laser absorption spectrometry to measure 152Gd:160Gd isotope ratios in micron-size particles. The diode lasers are tuned to specific isotopes in two different atomic transitions at 405.9 nm (152Gd) and 413.4 nm (160Gd) and directed collinearly through the laser ablation plume, separated on a diffraction grating, and detected with photodiodes to monitor transient absorption signals on a shot-by-shot basis. The method has been characterized first using Gd metal foil and then with particles of GdCl3?xH20 as binary and ternary mixtures with 152Gd:160Gd isotope ratios ranging from 0.01 to 0.43. These particulate mixtures have been diluted with Columbia River sediment powder (SRM 4350B) to simulate environmental samples and we show the method is capable of detecting a few highly enriched particles in the presence of > 100-fold excess of low-enrichment particles, even when the Gd-bearing particles are a minor component (0.08%) in the SRM powder and widely dispersed (1178 particles detected in 800 000 ablation laser shots). The implications for monitoring 235U:238U enrichment ratios, as related to the nuclear industry, are discussed

  1. Imaging the ultrafast Kerr effect, free carrier generation, relaxation and ablation dynamics of Lithium Niobate irradiated with femtosecond laser pulses

    SciTech Connect (OSTI)

    Garcia-Lechuga, Mario, E-mail: mario@io.cfmac.csic.es; Siegel, Jan, E-mail: j.siegel@io.cfmac.csic.es; Hernandez-Rueda, Javier; Solis, Javier [Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, 28006 Madrid (Spain)

    2014-09-21T23:59:59.000Z

    The interaction of high-power single 130 femtosecond (fs) laser pulses with the surface of Lithium Niobate is experimentally investigated in this work. The use of fs-resolution time-resolved microscopy allows us to separately observe the instantaneous optical Kerr effect induced by the pulse and the generation of a free electron plasma. The maximum electron density is reached 550?fs after the peak of the Kerr effect, confirming the presence of a delayed carrier generation mechanism. We have also observed the appearance of transient Newton rings during the ablation process, related to optical interference of the probe beam reflected at the front and back surface of the ablating layer. Finally, we have analyzed the dynamics of the photorefractive effect on a much longer time scale by measuring the evolution of the transmittance of the irradiated area for different fluences below the ablation threshold.

  2. ablation mass spectrometry: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and laser ablation electrospray ionization mass Chemistry Websites Summary: -mass spectrometry (DESI-MS) and laser ablation electrospray ionization-MS (LAESI-MS) were used to...

  3. Understanding plume splitting of laser ablated plasma: A view from ion distribution dynamics

    SciTech Connect (OSTI)

    Wu, Jian; Li, Xingwen; Wei, Wenfu; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

    2013-11-15T23:59:59.000Z

    Plume splitting in low-pressure ambient air was understood in view of ion distribution dynamics from the laser ablated Al plasma (1064 nm 0.57 J/mm{sup 2}) by combining fast photography and spatially resolved spectroscopy. In the beginning, the spectral lines were mainly from the Al III ion. Then, the Bragg peak in stopping power of the ambient gas to Al III could be the dominant reason for the enhanced emission from the fast moving part, and the recombination of Al III to Al I-II ions near the target surface was response to the radiations from the slow moving/stationary part. As the ambient gas pressure increased, stopping distances of the Al III decreased, and radiation from the air ions became pronounced. The laser shadowgraph image at 1100 Pa indicated that the shock wave front located between the fast moving and slow moving parts. Electron densities of the fast moving plasma, which peaked at the plasma front, were on the order of 10{sup 16} cm{sup ?3}, and the electron temperatures were 2–3 eV.

  4. Resonant high-order harmonic generation from plasma ablation: Laser intensity dependence of the harmonic intensity and phase

    SciTech Connect (OSTI)

    Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Str. 2a, D-12489 Berlin (Germany)

    2010-02-15T23:59:59.000Z

    Experimentally observed strong enhancement of a single high-order harmonic in harmonic generation from low-ionized laser plasma ablation is explained as resonant harmonic generation. The resonant harmonic intensity increases regularly with the increase of the laser intensity, while the phase of the resonant harmonic is almost independent of the laser intensity. This is in sharp contrast with the usual plateau and cutoff harmonics, the intensity of which exhibits wild oscillations while its phase changes rapidly with the laser intensity. The temporal profile of a group of harmonics, which includes the resonant harmonic, has the form of a broad peak in each laser-field half cycle. These characteristics of resonant harmonics can have an important application in attoscience. We illustrate our results using examples of Sn and Sb plasmas.

  5. A Langmuir Probe Diagnostic for Use in Inhomogeneous, Time-Varying Plasmas Produced by High-Energy Laser Ablation

    SciTech Connect (OSTI)

    Patterson, J R; Emig, J A; Fournier, K B; Jenkins, P P; Trautz, K M; Seiler, S W; Davis, J F

    2012-05-01T23:59:59.000Z

    Langmuir probes (LP) are used extensively to characterize plasma environments produced by radio frequency, pulsed plasma thrusters, and laser ablation. We discuss here the development of a LP diagnostic to examine high-density, high-temperature inhomogeneous plasmas such as those that can be created at the University of Rochester's Laboratory for Laser Energetics OMEGA facility. We have configured our diagnostic to examine the velocity of the plasma expanding from the target. We observe velocities of approximately 16-17 cm/{micro}s, with individual LP currents displaying complex structures, perhaps due to the multiple atomic species and ionization states that exist.

  6. Isotope Enrichment Detection by Laser Ablation - Dual Tunable Diode Laser Absorption Spectrometry

    SciTech Connect (OSTI)

    Anheier, Norman C.; Bushaw, Bruce A.

    2009-07-01T23:59:59.000Z

    The rapid global expansion of nuclear energy is motivating the expedited development of new safeguards technology to mitigate potential proliferation threats arising from monitoring gaps within the uranium enrichment process. Current onsite enrichment level monitoring methods are limited by poor sensitivity and accuracy performance. Offsite analysis has better performance, but this approach requires onsite hand sampling followed by time-consuming and costly post analysis. These limitations make it extremely difficult to implement comprehensive safeguards accounting measures that can effectively counter enrichment facility misuse. In addition, uranium enrichment by modern centrifugation leads to a significant proliferation threat, since the centrifuge cascades can quickly produce a significant quantity of highly enriched uranium (HEU). The Pacific Northwest National Laboratory is developing an engineered safeguards approach having continuous aerosol particulate collection and uranium isotope analysis to provide timely detection of HEU production in a low enriched uranium facility. This approach is based on laser vaporization of aerosol particulate samples, followed by wavelength tuned laser diode spectroscopy, to characterize the 235U/238U isotopic ratio by subtle differences in atomic absorption wavelengths arising from differences in each isotope’s nuclear mass, volume, and spin (hyperfine structure for 235U). Environmental sampling media is introduced into a small, reduced pressure chamber, where a focused pulsed laser vaporizes a 10 to 20-µm sample diameter. The ejected plasma forms a plume of atomic vapor. A plume for a sample containing uranium has atoms of the 235U and 238U isotopes present. Tunable diode lasers are directed through the plume to selectively excite each isotope and their presence is detected by monitoring absorbance signals on a shot-to-shot basis. Single-shot detection sensitivity approaching the femtogram range and abundance uncertainty less than 10% have been demonstrated with measurements on surrogate materials. In this paper we present measurement results on samples containing background materials (e.g., dust, minerals, soils) laced with micron-sized target particles having isotopic ratios ranging from 1 to 50%.

  7. Isotopic Analysis of Uranium in NIST SRM Glass by Femtosecond Laser Ablation

    SciTech Connect (OSTI)

    Duffin, Andrew M.; Hart, Garret L.; Hanlen, Richard C.; Eiden, Gregory C.

    2013-05-19T23:59:59.000Z

    We employed femtosecond Laser Ablation Multicollector Inductively Coupled Mass Spectrometry for the 11 determination of uranium isotope ratios in a series of standard reference material glasses (NIST 610, 612, 614, and 12 616). This uranium concentration in this series of SRM glasses is a combination of isotopically natural uranium in 13 the materials used to make the glass matrix and isotopically depleted uranium added to increase the uranium 14 elemental concentration across the series. Results for NIST 610 are in excellent agreement with literature values. 15 However, other than atom percent 235U, little information is available for the remaining glasses. We present atom 16 percent and isotope ratios for 234U, 235U, 236U, and 238U for all four glasses. Our results show deviations from the 17 certificate values for the atom percent 235U, indicating the need for further examination of the uranium isotopes in 18 NIST 610-616. Our results are fully consistent with a two isotopic component mixing between the depleted 19 uranium spike and natural uranium in the bulk glass.

  8. Structural and optical properties of {beta}-FeSi{sub 2}/Si(100) prepared by laser ablation method

    SciTech Connect (OSTI)

    Kakemoto, H.; Makita, Y.; Obara, A.; Tsai, Y.; Sakuragi, S.; Ando, S.; Tsukamoto, T.

    1997-07-01T23:59:59.000Z

    {beta}-FeSi{sub 2} is a promising material for the application of various electronic, optoelectronic and energy devices. The authors present here the semiconducting properties of {beta}-FeSi{sub 2} films on Si(100) substrate prepared by laser ablation method. Samples were grown using poly-crystalline bulk {beta}-FeSi{sub 2} prepared by horizontal gradient freeze method. For the monitoring of growth, in-situ observation of ablation plume was made through fluorescence spectroscopy. Reflection of high-energy electron beam diffraction (RHEED) was also made in-situ to see the surface morphology. Characterization of the films by X-ray diffraction presented purely {beta}(220) orientation. Raman scattering measurements at room temperature also indicated that the grown films are semiconducting {beta}-FeSi{sub 2}. Optical absorption spectra at room temperature showed absorption coefficient higher than 10{sup 5} cm{sup {minus}1} above the band-gap ({approximately}1.2 eV). It was revealed that high quality semiconducting {beta}-FeSi{sub 2} films can be fabricated by laser ablation method without post-annealing.

  9. Long-Time Feedback in the Formation of Self-Organized Nanostructures upon Multipulse Femtosecond Laser Ablation

    SciTech Connect (OSTI)

    Reif, Juergen; Varlamova, Olga [Brandenburgische Technische Universitaet (BTU) Cottbus Universitaetsstr. 1, 03046 Cottbus (Germany); Cottbus JointLab, Erich-Weinert-Str. 1, 03046 Cottbus (Germany); Bounhalli, Mourad [Brandenburgische Technische Universitaet (BTU) Cottbus Universitaetsstr. 1, 03046 Cottbus (Germany); Laboratoire Hubert Curien, Universite Jean Monnet, Saint-Etienne (France); Arguirov, Tzanimir [Cottbus JointLab, Erich-Weinert-Str. 1, 03046 Cottbus (Germany); IHP-Leibniz-Institut fuer innovative Mikroelektronik, Frankfurt (Germany)

    2010-10-08T23:59:59.000Z

    The self-organization feedback in nanostructures (ripples) formation upon femtosecond laser ablation is investigated in detail, with particular emphasis on its dynamics. We study the influence of time separation between successive pulses on both the size and complexity of the nanostructures and on the size of the modified surface area. By varying the pulse separation between 1 ms and 1 s (rep. rate between 1 kHz and 1 Hz), we find that both modified area as well as pattern feature size and complexity decrease with increasing pulse-to-pulse delay, indicating that the coupling efficiency between laser and target increases with increasing repetition rate. Structure formation resulting from surface instability, induced by the laser impact, suggests that the laser-induced instability results in a transient increase of absorption probability, slowly decaying in time. The stronger this transient absorption, the better is the coupling for the succeeding pulse, thus resulting in a positive feedback. Experimental results indicate that the lifetime of the feedback can last up to one second and longer.In addition, a persisting modulated spatial modification of crystalline properties is observed well beyond the ablation spot, though no apparent influence on surface morphology is seen. Mapping the band-to-band photoluminescence from silicon indicates a dramatic increase of non-radiative recombination compared to unaffected material.

  10. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    SciTech Connect (OSTI)

    Perdian, David C.

    2009-08-19T23:59:59.000Z

    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  11. Direct periodic patterning of GaN-based light-emitting diodes by three-beam interference laser ablation

    SciTech Connect (OSTI)

    Kim, Jeomoh; Ji, Mi-Hee; Detchprohm, Theeradetch [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); Yuan, Dajun; Guo, Rui [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); Liu, Jianping [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125 (China); Asadirad, Mojtaba [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Kwon, Min-Ki [Department of Photonic Engineering, Chosun University, Seosuk-dong, Gwangju 501-759 (Korea, Republic of); Dupuis, Russell D. [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Das, Suman [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Ryou, Jae-Hyun, E-mail: jryou@uh.edu [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Department of Mechanical Engineering and Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, Texas 77204-4006 (United States)

    2014-04-07T23:59:59.000Z

    We report on the direct patterning of two-dimensional periodic structures in GaN-based light-emitting diodes (LEDs) through laser interference ablation for the fast and reliable fabrication of periodic micro- and nano-structures aimed at enhancing light output. Holes arranged in a two-dimensional hexagonal lattice array having an opening size of 500?nm, depth of 50?nm, and a periodicity of 1??m were directly formed by three-beam laser interference without photolithography or electron-beam lithography processes. The laser-patterned LEDs exhibit an enhancement in light output power of 20% compared to conventional LEDs having a flat top surface without degradation of electrical and optical properties of the top p-GaN layer and the active region, respectively.

  12. Developing the model of laser ablation by considering the interplay between emission and expansion of aluminum plasma

    SciTech Connect (OSTI)

    Rezaei, F.; Tavassoli, S. H. [Laser and Plasma Research Institute, ShahidBeheshti University, 19396 4716, G. C., Evin, Tehran (Iran, Islamic Republic of)

    2013-01-15T23:59:59.000Z

    In the present study, the ablation behavior of aluminum target and its plasma radiation in noble ambient gases by a laser pulse with wavelength of 266 nm and pulse duration of 10 ns are numerically studied. A thermal model of laser ablation considering heat conduction, Euler equations, Saha-Eggert equations, Knudsen layer, mass and energy balance relations and optical shielding effects are used for calculation of plasma parameters. Effects of excitation energy on plasma expansion and its emissivity are investigated. Time and spatial-resolved plasma emission including bremsstrahlung, recombination and spectral emission at early delay times after laser irradiation is obtained. Effects of two ambient gases (He and Ar) as well as different gas pressures of 100, 300, 500, and 760 Torr on plasma expansion and its spectrum are studied. Results illustrate that at initial delay times, especially at high noble gas pressures, ionic lines have the maximum intensities, while at later times neutral lines dominate. When the pressure of ambient gas increases, a confinement of the plasma plume is predicted and the intensity of neutral lines decreases. Continuous emission increases with wavelength in both ambient gases. Spatially resolved analysis shows that an intense continuous emission is predicted next to the sample surface decreasing with distance from the latter.

  13. Pulsed laser kinetic studies of liquids under high pressure

    SciTech Connect (OSTI)

    Eyring, E.M.

    1992-09-22T23:59:59.000Z

    A laser flash photolysis kinetic study of 2,2{prime}-bipyridine bidentate chelating ligands with one claw in the first coordination sphere of a molybdenum carbonyl complex has been completed at pressures up to 150 MPa. The reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2{prime}-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Stability constants for lithium ion complexes with crown ethers in a room temperature molten salt, fluorescence quantum yields for cresyl violet and several other dyes in solution, and the oxidation of alcohols by OsO{sub 4} have also been investigated.

  14. Summer 2010 Pulsed Laser Ablation of solid targets in a liquid

    E-Print Network [OSTI]

    Baltisberger, Jay H.

    is exposed to is extreme. #12;ARC DISCHARGE- APPROX. 30% OF CARBON FORMS NANOTUBES. CHEMICAL VAPOR DEPOSITION Cyclohexane Pentane Toluene Ammonia This is a solid substance that was used in the ablation process

  15. Computational study of cooling rates and recrystallization kinetics in short pulse laser quenching of metal targets

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Computational study of cooling rates and recrystallization kinetics in short pulse laser quenching@virginia.edu Abstract. Short pulse laser melting and resolidification of a metal target are investigated in continuum in the simulations. 1. Introduction Short pulse laser processing of metal surfaces typically involves fast transient

  16. Isotope Enrichment Detection by Laser Ablation - Laser Absorption Spectrometry: Automated Environmental Sampling and Laser-Based Analysis for HEU Detection

    SciTech Connect (OSTI)

    Anheier, Norman C.; Bushaw, Bruce A.

    2010-01-01T23:59:59.000Z

    The global expansion of nuclear power, and consequently the uranium enrichment industry, requires the development of new safeguards technology to mitigate proliferation risks. Current enrichment monitoring instruments exist that provide only yes/no detection of highly enriched uranium (HEU) production. More accurate accountancy measurements are typically restricted to gamma-ray and weight measurements taken in cylinder storage yards. Analysis of environmental and cylinder content samples have much higher effectiveness, but this approach requires onsite sampling, shipping, and time-consuming laboratory analysis and reporting. Given that large modern gaseous centrifuge enrichment plants (GCEPs) can quickly produce a significant quantity (SQ ) of HEU, these limitations in verification suggest the need for more timely detection of potential facility misuse. The Pacific Northwest National Laboratory (PNNL) is developing an unattended safeguards instrument concept, combining continuous aerosol particulate collection with uranium isotope assay, to provide timely analysis of enrichment levels within low enriched uranium facilities. This approach is based on laser vaporization of aerosol particulate samples, followed by wavelength tuned laser diode spectroscopy to characterize the uranium isotopic ratio through subtle differences in atomic absorption wavelengths. Environmental sampling (ES) media from an integrated aerosol collector is introduced into a small, reduced pressure chamber, where a focused pulsed laser vaporizes material from a 10 to 20-µm diameter spot of the surface of the sampling media. The plume of ejected material begins as high-temperature plasma that yields ions and atoms, as well as molecules and molecular ions. We concentrate on the plume of atomic vapor that remains after the plasma has expanded and then cooled by the surrounding cover gas. Tunable diode lasers are directed through this plume and each isotope is detected by monitoring absorbance signals on a shot-to-shot basis. The media is translated by a micron resolution scanning system, allowing the isotope analysis to cover the entire sample surface. We also report, to the best of our knowledge, the first demonstration of laser-based isotopic measurements on individual micron-sized particles that are minor target components in a much larger heterogeneous mix of ‘background’ particles. This composition is consistent with swipe and environmental aerosol samples typically collected for safeguards ES purposes. Single-shot detection sensitivity approaching the femtogram range and relative isotope abundance uncertainty better than 10% has been demonstrated using gadolinium isotopes as surrogate materials.

  17. High spatial resolution mapping of deposition layers on plasma facing materials by laser ablation microprobe time-of-flight mass spectroscopy

    SciTech Connect (OSTI)

    Xiao, Qingmei; Li, Cong; Hai, Ran; Zhang, Lei; Feng, Chunlei; Ding, Hongbin, E-mail: hding@dlut.edu.cn [School of Physics and Optical Electronic Technology, Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Chinese Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Zhou, Yan; Yan, Longwen; Duan, Xuru [Southwestern Institute of Physics, P.O. Box 432, No. 3 South Section 3, Circle Road 2, Chengdu 610041, Sichuan (China)

    2014-05-15T23:59:59.000Z

    A laser ablation microprobe time-of-flight mass spectroscopy (LAM-TOF-MS) system with high spatial resolution, ?20 nm in depth and ?500 ?m or better on the surface, is developed to analyze the composition distributions of deposition layers on the first wall materials or first mirrors in tokamak. The LAM-TOF-MS system consists of a laser ablation microprobe combined with a TOF-MS and a data acquisition system based on a LabVIEW program software package. Laser induced ablation combined with TOF-MS is an attractive method to analyze the depth profile of deposited layer with successive laser shots, therefore, it can provide information for composition reconstruction of the plasma wall interaction process. In this work, we demonstrate that the LAM-TOF-MS system is capable of characterizing the depth profile as well as mapping 2D composition of deposited film on the molybdenum first mirror retrieved from HL-2A tokamak, with particular emphasis on some of the species produced during the ablation process. The presented LAM-TOF-MS system provides not only the 3D characterization of deposition but also the removal efficiency of species of concern.

  18. Laser Ablation of Metals Johannes Roth, Carolina Trichet, Hans-Rainer-Trebin, and Steffen Sonntag

    E-Print Network [OSTI]

    Roth, Johannes

    radiation. It is a technology which gains increasingly greater importance for drilling, eroding, welding especially, a large number of new processing methods were developed. A deeper understanding of the ablation natural. IMD has been adapted to new computer architectures and optimized continuously. Thus it is very

  19. In situ diagnostic of the size distribution of nanoparticles generated by ultrashort pulsed laser ablation in vacuum

    SciTech Connect (OSTI)

    Bourquard, Florent; Loir, Anne-Sophie; Donnet, Christophe; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr [Université de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Université Jean Monnet, Saint-Étienne (France)] [Université de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Université Jean Monnet, Saint-Étienne (France)

    2014-03-10T23:59:59.000Z

    We aim to characterize the size distribution of nanoparticles located in the ablation plume produced by femtosecond laser interaction. The proposed method relies on the use of white-light extinction spectroscopy setup assisted by ultrafast intensified temporal gating. This method allows measurement of optical absorbance of a nickel nanoparticles cloud. Simulation of the extinction section of nickel nanoparticles size distributions has been developed in order to compare the measured optical absorbance to the optical extinction by theoretical and experimental nanoparticles size distributions (measured by scanning electron microscopy). A good agreement has been found between the in situ measured optical absorbance and the optical extinction cross section calculated from ex situ nanoparticles size distribution measurements.

  20. High throughput solar cell ablation system

    DOE Patents [OSTI]

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

    2012-09-11T23:59:59.000Z

    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  1. High throughput solar cell ablation system

    DOE Patents [OSTI]

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

    2014-10-14T23:59:59.000Z

    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  2. Representative sampling using single-pulse laser ablation with inductively coupled plasma mass spectroscopy

    E-Print Network [OSTI]

    Liu, Haichen; Mao, Xianglei; Russo, Richard E.

    2001-01-01T23:59:59.000Z

    U also achieved a representative value at high irradiance.Representative sampling using single-pulse laser ablationvalue close to the representative level. Segregation during

  3. Analyses of femtosecond laser ablation of Ti, Zr and Hf. D. Grojo, J. Hermann*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    that two plasma components with different expansion velocities are generated by the ultra-short laser sources, the thermal damage of the material is strongly reduced when using ultra-short laser pulses fluence and target material. The results are discussed in terms of mechanisms responsible for ultra-short

  4. Photonic crystal formation on optical nanofibers using femtosecond laser ablation technique

    E-Print Network [OSTI]

    K. P. Nayak; K. Hakuta

    2012-10-29T23:59:59.000Z

    We demonstrate that thousands of periodic nano-craters are fabricated on a subwavelength-diameter tapered optical fiber, an optical nanofiber, by irradiating with just a single femtosecond laser pulse. A key aspect of the fabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. We also demonstrate that such periodic structures on the nanofiber, act as a 1-D photonic crystal (PhC). Such PhC structures on the nanofiber will strongly enhance the field confinement in such a tapered fiber-based system and may open new avenues in nanophotonics and quantum information technology.

  5. Investigation of optical limiting properties of Aluminium nanoparticles prepared by pulsed laser ablation in different carrier media

    SciTech Connect (OSTI)

    Kuladeep, Rajamudili; Jyothi, L.; Narayana Rao, D. [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)] [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Prakash, P.; Mayank Shekhar, S. [Center of Excellence in Lasers and Optoelectronic Sciences, International School of Photonics, Cochin University of Science and Technology, Kochi (India)] [Center of Excellence in Lasers and Optoelectronic Sciences, International School of Photonics, Cochin University of Science and Technology, Kochi (India); Durga Prasad, M. [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)] [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)

    2013-12-28T23:59:59.000Z

    In this communication, we carried out the systematic investigation of nonlinear absorption and scattering properties of Aluminium nanoparticles (Al NPs) in various polar and non-polar solvents. Al NPs were synthesized with pulsed Nd:YAG laser operated at 1064 nm by ablating Al target in polar and non-polar liquid environment like chloroform, chlorobenzene, toluene, benzene, and carbon tetrachloride. Synthesized Al NPs colloids of various solvents differ in appearance and UV-Vis extinction spectra exhibit absorption in the UV region. The characterization of Al NPs performed by Transmission electron microscopy (TEM) studies reveal that NPs are made up of a well crystallized Al inner part (bright zone) embedded with an amorphous metal Al shell (dark region). Growth, aggregation, and precipitation mechanisms which influence the optical properties and stability of NPs are found to be related to the dipole moment of the surrounding liquid environment. The nonlinear absorption and scattering studies are performed by open aperture Z-scan technique with 532 nm under nanosecond pulse excitation. The Z-scan measurements are fitted theoretically to estimate both two-photon absorption (TPA) and nonlinear scattering (NLS) coefficients. In polar solvents like chlorobenzene, chloroform synthesized Al NPs exhibited higher TPA, NLS coefficient values, and lower optical limiting threshold values in comparison with partially polar solvent like toluene and non-polar solvents like benzene and carbontetrachloride. These results indicate the potential use of Al NPs as a versatile optical limiting material.

  6. Nanostructured europium oxide thin films deposited by pulsed laser ablation of a metallic target in a He buffer atmosphere

    SciTech Connect (OSTI)

    Luna, H.; Franceschini, D. F.; Prioli, R.; Guimaraes, R. B.; Sanchez, C. M.; Canal, G. P.; Barbosa, M. D. L.; Galvao, R. M. O. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cx. Postal 68528, Rio de Janeiro, RJ 21941-972 (Brazil); Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ 24210-346 (Brazil); Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, Rua Marques de Sao Vicente 225, 22453-970, Rio de Janeiro, RJ (Brazil); Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ 24210-346 (Brazil); Centro Brasileiro de Pesquisas Fisicas, Laboratorio de Plasmas Aplicados, Rua Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil); Instituto de Fisica, Departamento de Fisica Nuclear, Universidade de Sao Paulo, Caixa Postal 66328, 05315-970, Sao Paulo, SP (Brazil); Centro Brasileiro de Pesquisas Fisicas, Laboratorio de Plasmas Aplicados, Rua Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil)

    2010-09-15T23:59:59.000Z

    Nanostrucured europium oxide and hydroxide films were obtained by pulsed Nd:YAG (532 nm) laser ablation of a europium metallic target, in the presence of a 1 mbar helium buffer atmosphere. Both the produced film and the ambient plasma were characterized. The plasma was monitored by an electrostatic probe, for plume expansion in vacuum or in the presence of the buffer atmosphere. The time evolution of the ion saturation current was obtained for several probe to substrate distances. The results show the splitting of the plume into two velocity groups, being the lower velocity profile associated with metal cluster formation within the plume. The films were obtained in the presence of helium atmosphere, for several target-to-substrate distances. They were analyzed by Rutherford backscattering spectrometry, x-ray diffraction, and atomic force microscopy, for as-deposited and 600 deg. C treated-in-air samples. The results show that the as-deposited samples are amorphous and have chemical composition compatible with europium hydroxide. The thermally treated samples show x-ray diffraction peaks of Eu{sub 2}O{sub 3}, with chemical composition showing excess oxygen. Film nanostructuring was shown to be strongly correlated with cluster formation, as shown by velocity splitting in probe current versus time plots.

  7. Catalytic nanoparticles for carbon nanotube growth synthesized by through thin film femtosecond laser ablation

    E-Print Network [OSTI]

    Geohegan, David B.

    within the distribution, suggesting that nanoparticle formation by gas phase condensation was not at play techniques were largely the result of condensation of a laser-induced plume in a background gas. Femtosecond of divergence of ~2.5º) which were cleanly deposited onto different supports for analysis. TEM showed

  8. Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle Cormier-Michel,1,2

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle of laser wakefield accelerators using particle-in-cell codes are investigated. A dark current free laser wakefield accelerator stage, in which no trapping of background plasma electrons into the plasma wave should

  9. Short-interval multi-laser Thomson scattering measurements of hydrogen pellet ablation in LHD

    SciTech Connect (OSTI)

    Yasuhara, R., E-mail: yasuhara@nifs.ac.jp; Sakamoto, R.; Yamada, I.; Motojima, G.; Hayashi, H. [National Institute for Fusion Science, 322–6 Oroshi-cho, Toki 509–5292 (Japan)

    2014-11-15T23:59:59.000Z

    Thomson scattering forms an important aspect of measuring the electron density and temperature profiles of plasmas. In this study, we demonstrate Thomson scattering measurements obtained over a short interval (<1 ms) by using an event triggering system with a multi-laser configuration. We attempt to use our system to obtain the electron temperature and density profiles before and immediately after pellet injection into the large helical device. The obtained profiles exhibit dramatic changes after pellet injection as per our shot-by-shot measurements. We believe that this measurement technique will contribute towards a better understanding of the physics of the pellet deposition.

  10. Pulsed laser kinetic studies of liquids under high pressure

    SciTech Connect (OSTI)

    Eyring, E.M.

    1993-06-21T23:59:59.000Z

    Experiments have been developed for measuring the rates of chemical reactions liquids and in supercritical Co[sub 2]. A pulsed (Q-switch) Nd:YAG laser at 355 nm was the pump beam for laser flash photolysis studies of molybdenum and tungsten hexacarbonyls undergoing ligand displacement reactions by bidentate chelating agents such as 2,2[prime]-bipyridine in toluene. Experiments were carried out at 0.1 to 150 MPa. In the case of molybdenum complexes, the reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2[prime]-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Similar high pressure flash photolysis experiments with tungsten hexacarbonyl have also been completed. The concentration dependence of the fluorescence and nonradiative decay quantum yields for cresyl violet in several solvent have been reported as well as stability constants for the complexation of lithium ion by four different crown ethers dissolved in a room temperature molten salt.

  11. Kinetic simulation studies of laser-triggering in the Z gas switch

    SciTech Connect (OSTI)

    Welch, D. R.; Rose, D. V.; Thoma, C.; Clark, R. E.; Miller, C.; Madrid, E. A.; Zimmerman, W. R. [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States)] [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States); Rambo, P. K.; Schwarz, J.; Savage, M.; Atherton, B. W. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1196 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-1196 (United States)

    2013-08-15T23:59:59.000Z

    Advanced z-pinch accelerators require precise timing of multiple mega-ampere drivers to deliver terawatt power. The triggering of these drivers is now largely initiated by laser ionization of gas switches. In this paper, we discuss detailed fully kinetic simulation of the Z laser-triggered gas switch involving detailed finite-difference time-domain particle-in-cell Monte Carlo modeling of the trigger section of the switch. Other components of the accelerator from the Marx bank through the pulse-forming line are described as circuit elements. The simulations presented here build on a recently developed model of electro-negative gas breakdown and streamer propagation that included photons produced from de-excited neutrals. New effects include multi-photon ionization of the gas in a prescribed laser field. The simulations show the sensitivity of triggering to laser parameters including focal plane within the anode-cathode gap of the trigger section of the switch, intensity at focus, and laser pulse length. Detailed electromagnetic simulations of the trigger section with circuit modeling of the upstream and downstream components are largely in agreement with Z data and demonstrate a new capability.

  12. JOURNAL OF MATERIALS SCIENCE 31 (1996) 2801 2805 Laser ablation of diamond fibres and a diamond fibre

    E-Print Network [OSTI]

    Bristol, University of

    .been embedded in Ti-6A1-4V alloy to produce a diamond fibre-reinforced composite. Both the fibres and a diamond fibre-reinforced titanium alloy composite. 2. Experimental procedure Fibres have been made of a diamond-coated fibre after localized ablations is shown tn Fig. 1. The areas of the diamond surface

  13. ablation laser spectrometer

    E-Print Network [OSTI]

    to reduce the formation of unwanted byproducts during gasification. NREL validated the ability of the system gasification. Potential Impact This combined platform used for the measurement and analysis of biomass cell

  14. Diesel combustion: an integrated view combining laser diagnostics, chemical kinetics, and empirical validation

    SciTech Connect (OSTI)

    Akinyami, O C; Dec, J E; Durrett, R P; Flynn, P F; Hunter, G L; Loye, A O; Westbrook, C

    1999-02-01T23:59:59.000Z

    This paper proposes a structure for the diesel combustion process based on a combination of previously published and new results. Processes are analyzed with proven chemical kinetic models and validated with data from production-like direct injection diesel engines. The analysis provides new insight into the ignition and particulate formation processes, which combined with laser diagnostics, delineates the two-stage nature of combustion in diesel engines. Data are presented to quantify events occurring during the ignition and initial combustion processes that form soot precursors. A framework is also proposed for understanding the heat release and emission formation processes.

  15. Ablation of film stacks in solar cell fabrication processes

    DOE Patents [OSTI]

    Harley, Gabriel; Kim, Taeseok; Cousins, Peter John

    2013-04-02T23:59:59.000Z

    A dielectric film stack of a solar cell is ablated using a laser. The dielectric film stack includes a layer that is absorptive in a wavelength of operation of the laser source. The laser source, which fires laser pulses at a pulse repetition rate, is configured to ablate the film stack to expose an underlying layer of material. The laser source may be configured to fire a burst of two laser pulses or a single temporally asymmetric laser pulse within a single pulse repetition to achieve complete ablation in a single step.

  16. Simple formula for the interspaces of periodic grating structures self-organized on metal surfaces by femtosecond laser ablation

    SciTech Connect (OSTI)

    Hashida, Masaki; Ikuta, Yoshinobu; Miyasaka, Yasuhiro; Tokita, Shigeki; Sakabe, Shuji [ARCBS, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan and Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-8502 (Japan)] [ARCBS, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan and Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-8502 (Japan)

    2013-04-29T23:59:59.000Z

    Self-organized grating structures formed on Mo and Ti metal surfaces irradiated with femtosecond laser pulses at wavelengths of 800 and 400 nm are investigated by electron microscopy. We observe the formation of the self-organized grating structures on the metals irradiated with 400-nm laser pulses at low laser fluence in narrow fluence ranges. The interspaces of the grating structure depend on the wavelength and fluence of the laser. We find that the dependence of the grating interspaces on laser fluence can be explained by a simple formula for induction of a surface-plasma wave through the parametric decay of laser light.

  17. Laser ablation-inductively coupled plasma-mass spectrometry: Examinations of the origins of polyatomic ions and advances in the sampling of particulates

    SciTech Connect (OSTI)

    Witte, Travis

    2011-11-30T23:59:59.000Z

    This dissertation provides a general introduction to Inductively coupled plasma-mass spectrometry (ICP-MS) and laser ablation (LA) sampling, with an examination of analytical challenges in the employment of this technique. It discusses the origin of metal oxide ions (MO+) in LA-ICP-MS, as well as the effect of introducing helium and nitrogen to the aerosol gas flow on the formation of these polyatomic interferences. It extends the study of polyatomic ions in LA-ICP-MS to metal argide (MAr+) species, an additional source of possible significant interferences in the spectrum. It describes the application of fs-LA-ICP-MS to the determination of uranium isotope ratios in particulate samples.

  18. ablation mass spectroscopy: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ranges. Furthermore, cw CRDS techniques are difficult to applyHigh resolution pulsed infrared cavity ringdown spectroscopy: Application to laser ablated carbon Cohen, Ronald...

  19. ablation ambient pressure: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    molecular imaging by laser ablation electrospray ionization mass spectrometry with ion mobility separation Chemistry Websites Summary: mouse brain sections) were imaged under...

  20. Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen-Iodine Laser System

    E-Print Network [OSTI]

    Carroll, David L.

    Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds levels

  1. ORIGINAL RESEARCH Noninvasive Measurement of Ablation Crater Size

    E-Print Network [OSTI]

    Chen, Zhongping

    proportional to laser power, whereas crater width and the zone of thermal injury appear to be unrelatedORIGINAL RESEARCH Noninvasive Measurement of Ablation Crater Size and Thermal Injury After CO2 at 10 m resolution, and the thermal disruption after laser ablation were identified by OCT. OCT

  2. Strontium isotope evidence of Neanderthal mobility at the site of Lakonis, Greece using laser-ablation PIMMS

    E-Print Network [OSTI]

    Smith, Tanya M.

    Strontium isotope evidence of Neanderthal mobility at the site of Lakonis, Greece using laser-Speleology of Southern Greece, Ardittou 34b, 11636 Athens, Greece Received 31 May 2007; received in revised form 25 July third molar from the site of Lakonis, Greece, dating to ca. 40,000 years ago. The tooth was found

  3. Studies of ion kinetic effects in shock-driven inertial confinement fusion implosions at OMEGA and the NIF and magnetic reconnection using laser-produced plasmas at OMEGA

    E-Print Network [OSTI]

    Rosenberg, Michael Jonathan

    2014-01-01T23:59:59.000Z

    Studies of ion kinetic effects during the shock-convergence phase of inertial confinement fusion (ICF) implosions and magnetic reconnection in strongly-driven, laser-produced plasmas have been facilitated by the use of ...

  4. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    DOE Patents [OSTI]

    Cross, J.B.; Cremers, D.A.

    1986-01-10T23:59:59.000Z

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species is described. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  5. Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) in

    E-Print Network [OSTI]

    Liu, Shilin

    Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide infrared heating laser pulse (10 ns)-induced temperature jump. The increases in the fluorescenceVersity of Hong Kong, Shatin N.T., Hong Kong ReceiVed June 4, 2007. In Final Form: July 7, 2007 The heating

  6. Langmuir probe measurements and mass spectrometry of plasma plumes generated by laser ablation of La{sub 0.4}Ca{sub 0.6}MnO{sub 3}

    SciTech Connect (OSTI)

    Chen, Jikun; Lippert, Thomas, E-mail: Thomas.lippert@psi.ch; Ojeda-G-P, Alejandro; Stender, Dieter; Schneider, Christof W.; Wokaun, Alexander [Department of General Energy Research, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Lunney, James G. [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland)

    2014-08-21T23:59:59.000Z

    The plasma formed in vacuum by UV nanosecond laser ablation of La{sub 0.4}Ca{sub 0.6}MnO{sub 3} in the fluence range of 0.8 to 1.9?J cm{sup ?2} using both Langmuir probe analysis and energy-resolved mass spectrometry has been studied. Mass spectrometry shows that the main positive ion species are Ca{sup +}, Mn{sup +}, La{sup +}, and LaO{sup +}. The Ca{sup +} and Mn{sup +} energy distributions are quite broad and lie in the 0–100?eV region, with the average energies increasing with laser fluence. In contrast, the La{sup +} and LaO{sup +} distributions are strongly peaked around 10?eV. The net time-of-arrival signal derived from the measured positive ion energy distributions is broadly consistent with the positive ion signal measured by the Langmuir probe. We also detected a significant number of O{sup ?} ions with energies in the range of 0 to 10?eV. The Langmuir probe was also used to measure the temporal variation of the electron density and temperature at 6?cm from the ablation target. In the period when O{sup ?} ions are found at this position, the plasma conditions are consistent with those required for significant negative oxygen ion formation, as revealed by studies on radio frequency excited oxygen plasma.

  7. Single Particle Laser Ablation | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of strong brown carbon chromophores. Citation: Laskin J, A Laskin, S Nizkorodov, PJ Roach, PA Eckert, MK Gilles, B Wang, HJ Lee, and Q Hu.2014."Molecular Selectivity of Brown...

  8. EMSL - Single Particle Laser Ablation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    MS) with high mass resolution (m&61636;m100,000). Solvent mixtures of acetonitrilewater and acetonitriletoluene were used to extract and ionize polar and non-polar...

  9. Pulsed laser kinetic studies of liquids under high pressure. Progress report, November 25, 1991--September 18, 1992

    SciTech Connect (OSTI)

    Eyring, E.M.

    1992-09-22T23:59:59.000Z

    A laser flash photolysis kinetic study of 2,2{prime}-bipyridine bidentate chelating ligands with one claw in the first coordination sphere of a molybdenum carbonyl complex has been completed at pressures up to 150 MPa. The reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2{prime}-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Stability constants for lithium ion complexes with crown ethers in a room temperature molten salt, fluorescence quantum yields for cresyl violet and several other dyes in solution, and the oxidation of alcohols by OsO{sub 4} have also been investigated.

  10. Comparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere and vacuum conditions

    E-Print Network [OSTI]

    Harilal, S. S.

    occur during the laser pulse in ns laser ablation, fs laser pulses are too short that these phenomena doComparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere Laser-induced breakdown spectroscopy Laser-produced plasma Plasma dynamics Femtosecond laser ablation

  11. Kinetics of laser pulse vaporization of uranium dioxide by mass spectrometry

    SciTech Connect (OSTI)

    Tsai, C.

    1981-11-01T23:59:59.000Z

    Safety analyses of nuclear reactors require knowledge of the evaporation behavior of UO/sub 2/ at temperatures well above the melting point of 3140 K. In this study, rapid transient heating of a small spot on a UO/sub 2/ specimen was accomplished by a laser pulse, which generates a surface temperature excursion. This in turn vaporizes the target surface and the gas expands into vacuum. The surface temperature transient was monitored by a fast-response automatic optical pyrometer. The maximum surface temperatures investigated range from approx. 3700 K to approx. 4300 K. A computer program was developed to simulate the laser heating process and calculate the surface temperature evolution. The effect of the uncertainties of the high temperature material properties on the calculation was included in a sensitivity study for UO/sub 2/ vaporization. The measured surface temperatures were in satisfactory agreements.

  12. Final report, Ames Mobile Laboratory Project: The development and operation of instrumentation in a mobile laboratory for in situ, real-time screening and characterization of soils using the laser ablation sampling technique

    SciTech Connect (OSTI)

    Anderson, M.S.; Braymen, S.D.

    1995-01-27T23:59:59.000Z

    The main focus of the Ames Laboratory`s Technology Integration Program, TIP, from May 1991 through December 1994 was the development, fabrication, and demonstration of a mobile instrumentation laboratory incorporating rapid in situ sampling systems for safe, rapid, and cost effective soil screening/characterization. The Mobile Demonstration Laboratory for Environmental Screening Technologies, MDLEST, containing the analysis instrumentation, along with surface and subsurface sampling probe prototypes employing the laser ablation sampling technique were chosen to satisfy the particular surface and subsurface soil characterization needs of the various Department of Energy facilities for determining the extent of heavy metal and radionuclide contamination. The MDLEST, a 44 foot long 5th wheel trailer, is easily configured for the analysis instrumentation and sampling system required for the particular site work. This mobile laboratory contains all of the utilities needed to satisfy the operating requirements of the various instrumentation installed. These utilities include, an electric generator, a chilled water system, process gases, a heating/air conditioning system, and computer monitoring and automatic operating systems. Once the MDLEST arrives at the job site, the instrumentation is aligned and calibration is completed, sampling and analysis operations begin. The sample is acquired, analyzed and the results reported in as little as 10 minutes. The surface sampling probe is used in two modes to acquire samples for analysis. It is either set directly on the ground over the site to be sampled, in situ sampling, or in a special fixture used for calibrating the sampling analysis system with standard soil samples, having the samples brought to the MDLEST. The surface sampling probe was used to in situ sample a flat concrete surface (nondestructively) with the ablated sample being analyzed by the instrumentation in the MDLEST.

  13. A Mass Spectrometry Study of Isotope Separation in the Laser Plume

    E-Print Network [OSTI]

    Suen, Timothy Wu

    2012-01-01T23:59:59.000Z

    Zhang, and J. A. Nees, “Isotope Enrichment in Laser-AblationA. Naik, “Comment on “Isotope Enrichment in Laser-AblationP. Pronko, “Isotope separation and enrichment by ultrafast

  14. Kinetic Electrostatic Electron Nonlinear (KEEN) Waves and their Interactions Driven by the Ponderomotive Force of Crossing Laser Beams

    E-Print Network [OSTI]

    Bedros Afeyan; K. Won; V. Savchenko; T. Johnston; A. Ghizzo; P. Bertrand

    2012-10-30T23:59:59.000Z

    We have found, using 1D periodic Vlasov-Poisson simulations, new nonlinear, nonstationary, stable, long lived, coherent structures in phase space, called kinetic electrostatic electron nonlinear (KEEN) waves. Ponderomotively driven for a short period of time, at a particular frequency and wavenumber, well inside the band gap that was thought to exist between electron plasma and electron acoustic wave frequencies, KEEN waves are seen to self-consistently form, and persist for thousands of plasma periods. KEEN waves are comprised of 4 or more significant phase-locked harmonic modes which persist only when driven sufficiently strongly. They also merge when two or more at different frequencies are driven sequentially. However, the final stable KEEN state that emerges is highly sensitive to their relative order of excitation. KEEN waves also interact quite strongly with electron plasma waves (EPW) especially when their harmonics are close to being resonant with the EPW frequency at the same k. The common assumption that whenever sufficiently large amplitude coherent laser energy is present in an unmagnetized plasma, EPWs and IAWs are the only waves with which the electromagnetic energy can interact coherently may require reconsideration.

  15. ccsd-00001265(version1):10Mar2004 Applied Physics A (2004) accepted Silicon clusters produced by femtosecond laser ablation: Non-thermal emission and

    E-Print Network [OSTI]

    Boyer, Edmond

    by using high-energy (6.4 eV) photons [9]. Multiple-charged cluster ions were formed in ps-laser stimulated and investigated using time-of- flight mass spectrometry. Two populations of the Si+ n clusters with different@crmcn.univ-mrs.fr etition rate, up to 30 mJ energy per pulse) operating at 800 nm. A part of the laser beam was selected

  16. Laser surface cleaning

    SciTech Connect (OSTI)

    Crivella, E.C.; Freiwald, J.; Freiwald, D.A.

    1996-12-31T23:59:59.000Z

    Decontamination of contaminated metal and material recycle, two of 31 priority needs identified by the D&D focus group, are the most promising applications for laser ablation within the DOE complex. F2 Associates has developed a robotic laser ablation system that is capable of high contamination rates, waste volume reduction, surface pore cleaning, and real-time characterization of materials. It is being demonstrated that this system will be the most cost-effective technology for metal decontamination and material recycle.

  17. MEASUREMENT OF ION BEAM FROM LASER ION SOURCE FOR RHIC Takeshi Kanesue, Kyushu University, Fukuoka 819-0395, Japan

    E-Print Network [OSTI]

    , vaporized and becomes plasma which is called laser ablation plasma then plasma expand adiabatically perpendicular to the target surface. Properties of Laser ablation plasma such as charge state distribution, and emittance of Au ions extracted from laser ablation plasma was measured. SINGLY CHARGED ION PRODUCTION We

  18. Expansion dynamics of laser produced plasma

    SciTech Connect (OSTI)

    Doggett, B.; Lunney, J. G. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2011-05-01T23:59:59.000Z

    We consider the applicability of the isentropic, adiabatic gas dynamical model of plume expansion for laser ablation in vacuum. We show that the model can be applied to ionized plumes and estimate the upper electron temperature limit on the applicability of the isentropic approximation. The model predictions are compared with Langmuir ion probe measurements and deposition profiles obtained for excimer laser ablation of silver.

  19. High pressure generation by hot electrons driven ablation

    SciTech Connect (OSTI)

    Piriz, A. R. [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energéticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)] [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energéticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Piriz, S. A. [Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid (Spain)] [Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Tahir, N. A. [GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)] [GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)

    2013-11-15T23:59:59.000Z

    A previous model [Piriz et al. Phys. Plasmas 19, 122705 (2012)] for the ablation driven by the hot electrons generated in collisionless laser-plasma interactions in the framework of shock ignition is revisited. The impact of recent results indicating that for a laser wavelength ? = 0.35 ?m the hot electron temperature ?{sub H} would be independent of the laser intensity I, on the resulting ablation pressure is considered. In comparison with the case when the scaling law ?{sub H}?(I?{sup 2}){sup 1/3} is assumed, the generation of the high pressures needed for driving the ignitor shock may be more demanding. Intensities above 10{sup 17} W/cm{sup 2} would be required for ?{sub H}=25?30 keV.

  20. An analysis of the kinetics of thermal damage and movement of damage front in laser irradiated egg white 

    E-Print Network [OSTI]

    Azeemi, Aamer Amjed

    1993-01-01T23:59:59.000Z

    Some of the major applications of laser surgery involve the photocoagulation of diseased tissue, with minimal or no damage to the surrounding healthy tissue. There is a growing need for a model for the quantification of thermal damage. The models...

  1. An analysis of the kinetics of thermal damage and movement of damage front in laser irradiated egg white

    E-Print Network [OSTI]

    Azeemi, Aamer Amjed

    1993-01-01T23:59:59.000Z

    Some of the major applications of laser surgery involve the photocoagulation of diseased tissue, with minimal or no damage to the surrounding healthy tissue. There is a growing need for a model for the quantification of thermal damage. The models...

  2. Phase field simulation of kinetic superheating and melting of aluminum nanolayer irradiated by pico- and femtosecond laser

    SciTech Connect (OSTI)

    Seok Hwang, Yong [Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States)] [Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States); Levitas, Valery I. [Departments of Aerospace Engineering, Mechanical Engineering, and Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)] [Departments of Aerospace Engineering, Mechanical Engineering, and Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2013-12-23T23:59:59.000Z

    Two melting mechanisms are reproduced and quantified for superheating and melting of Al nanolayer irradiated by pico- and femtosecond laser using the advanced phase-field approach coupled with mechanics and a two-temperature model. At heating rates Q?79.04 K/ps induced by picosecond laser, two-sided barrierless surface melting forms two solid-melt interfaces, which meet near the center of a sample. The temperature for surface melting is a linear function, and for complete melting it is a cubic function, of logQ. At Q?300 K/ps induced by femtosecond laser, barrierless and homogeneous melting (without nucleation) at the sample center occurs faster than due to interface propagation. Good agreement with experimental melting time was achieved in a range of 0.95?Q?1290 K/ps without fitting of material parameters.

  3. Integrated Kinetic Simulation of Laser-Plasma Interactions, Fast-Electron Generation and Transport in Fast Ignition

    SciTech Connect (OSTI)

    Kemp, A; Cohen, B; Divol, L

    2009-11-16T23:59:59.000Z

    We present new results on the physics of short-pulse laser-matter interaction of kilojoule-picosecond pulses at full spatial and temporal scale, using a new approach that combines a 3D collisional electromagnetic Particle-in-Cell code with an MHD-hybrid model of high-density plasma. In the latter, collisions damp out plasma waves, and an Ohm's law with electron inertia effects neglected determines the electric field. In addition to yielding orders of magnitude in speed-up while avoiding numerical instabilities, this allows us to model the whole problem in a single unified framework: the laser-plasma interaction at sub-critical densities, energy deposition at relativistic critical densities, and fast-electron transport in solid densities. Key questions such as the multi-picosecond temporal evolution of the laser energy conversion into hot electrons, the impact of return currents on the laser-plasma interaction, and the effect of self-generated electric and magnetic fields on electron transport will be addressed. We will report applications to current experiments.

  4. Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen*

    E-Print Network [OSTI]

    Fang-Yen, Christopher

    CHAPTER 6 Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen* , Christopher V. Identifying Cells in C. elegans III. Laser Ablation Theory and Apparatus A. Tissue Damage by Nanosecond and Femtosecond Lasers B. The Laser Apparatus IV. Laser Killing of Cells A. Procedures B. Experimental Design

  5. RAPID COMMUNICATION / COMMUNICATION RAPIDE Validation of Sr isotopes in otoliths by laser

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    RAPID COMMUNICATION / COMMUNICATION RAPIDE Validation of Sr isotopes in otoliths by laser ablation à plasma inductif avec multicollecteur après ablation au laser (LA-MC-ICPMS) et par spectrométrie de ratios using laser abla- tion multicollector inductively coupled plasma mass spectrometry (LA

  6. Infrared Spectroscopy of Laser Irradiated Dental Hard Tissues using the Advanced Light Source

    E-Print Network [OSTI]

    on the laser ablation/drilling process and may lead to a reduction in the ablation rate and efficiencyInfrared Spectroscopy of Laser Irradiated Dental Hard Tissues using the Advanced Light Source D Dental Sciences, San Francisco, CA 94143-0758, USA INTRODUCTION Infrared lasers are ideally suited

  7. Kinetic Electrostatic Electron Nonlinear (KEEN) Waves and their Interactions Driven by the Ponderomotive Force of Crossing Laser Beams

    E-Print Network [OSTI]

    Afeyan, Bedros; Savchenko, V; Johnston, T; Ghizzo, A; Bertrand, P

    2012-01-01T23:59:59.000Z

    We have found, using 1D periodic Vlasov-Poisson simulations, new nonlinear, nonstationary, stable, long lived, coherent structures in phase space, called kinetic electrostatic electron nonlinear (KEEN) waves. Ponderomotively driven for a short period of time, at a particular frequency and wavenumber, well inside the band gap that was thought to exist between electron plasma and electron acoustic wave frequencies, KEEN waves are seen to self-consistently form, and persist for thousands of plasma periods. KEEN waves are comprised of 4 or more significant phase-locked harmonic modes which persist only when driven sufficiently strongly. They also merge when two or more at different frequencies are driven sequentially. However, the final stable KEEN state that emerges is highly sensitive to their relative order of excitation. KEEN waves also interact quite strongly with electron plasma waves (EPW) especially when their harmonics are close to being resonant with the EPW frequency at the same k. The common assumptio...

  8. Pulsed laser kinetic studies of liquids under high pressure. Final technical report, April 1, 1990--March 31, 1993

    SciTech Connect (OSTI)

    Eyring, E.M.

    1993-06-21T23:59:59.000Z

    Experiments have been developed for measuring the rates of chemical reactions liquids and in supercritical Co{sub 2}. A pulsed (Q-switch) Nd:YAG laser at 355 nm was the pump beam for laser flash photolysis studies of molybdenum and tungsten hexacarbonyls undergoing ligand displacement reactions by bidentate chelating agents such as 2,2{prime}-bipyridine in toluene. Experiments were carried out at 0.1 to 150 MPa. In the case of molybdenum complexes, the reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2{prime}-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Similar high pressure flash photolysis experiments with tungsten hexacarbonyl have also been completed. The concentration dependence of the fluorescence and nonradiative decay quantum yields for cresyl violet in several solvent have been reported as well as stability constants for the complexation of lithium ion by four different crown ethers dissolved in a room temperature molten salt.

  9. Segmentation and visualization for cardiac ablation procedures

    E-Print Network [OSTI]

    Depa, Michal

    2011-01-01T23:59:59.000Z

    In this thesis, we present novel medical image analysis methods to improve planning and outcome evaluation of cardiac ablation procedures. Cardiac ablation is a common medical procedure that consists of burning cardiac ...

  10. Femtosecond laser processing of crystalline silicon

    E-Print Network [OSTI]

    Tran, D. V.

    This paper reports the surface morphologies and ablation of crystalline silicon wafers irradiated by infra-red 775 nm Ti:sapphire femtosecond laser. The effects of energy fluences (below and above single-pulse modification) ...

  11. Digital multimirror devices for precision laser micromachining

    E-Print Network [OSTI]

    DMD LIFT results 24 PMMA donors New 3D printing technology! BiTe semiconductor film New laser 3D printing facility...An ORC breakthrough 75 µm #12;Summary · DMDs are very useful for precise ablation

  12. Transhemangioma Ablation of Hepatocellular Carcinoma

    SciTech Connect (OSTI)

    Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

    2012-12-15T23:59:59.000Z

    Radiofrequency ablation (RFA) is a well-established treatment modality in the treatment of early hepatocellular carcinoma (HCC) [1]. Safe trajectory of the RFA probe is crucial in decreasing collateral tissue damage and unwarranted probe transgression. As a percutaneous technique, however, the trajectory of the needle is sometimes constrained by the available imaging plane. The presence of a hemangioma beside an HCC is uncommon but poses the question of safety related to probe transgression. We hereby describe a case of transhemangioma ablation of a dome HCC.

  13. Microwave Ablation Compared with Radiofrequency Ablation for Breast Tissue in an Ex Vivo Bovine Udder Model

    SciTech Connect (OSTI)

    Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen (Germany); Westphal, Saskia, E-mail: swestphal@ukaachen.de [RWTH Aachen University, Department of Pathology Aachen University Hospital (Germany); Isfort, Peter, E-mail: isfort@hia.rwth-aachen.de [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen (Germany); Braunschweig, Till, E-mail: tbraunschweig@ukaachen.de [RWTH Aachen University, Department of Pathology Aachen University Hospital (Germany); Penzkofer, Tobias, E-mail: penzkofer@hia.rwth-aachen.de; Bruners, Philipp, E-mail: bruners@rad.rwth-aachen.de [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen (Germany); Kichikawa, Kimihiko, E-mail: kkichika@naramed-u.ac.jp [Nara Medical University, Department of Radiology (Japan); Schmitz-Rode, Thomas, E-mail: smiro@hia.rwth-aachen.de; Mahnken, Andreas H., E-mail: mahnken@rad.rwth-aachen.de [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen (Germany)

    2012-08-15T23:59:59.000Z

    Purpose: To compare the effectiveness of microwave (MW) ablation with radiofrequency (RF) ablation for treating breast tissue in a nonperfused ex vivo model of healthy bovine udder tissue. Materials and Methods: MW ablations were performed at power outputs of 25W, 35W, and 45W using a 915-MHz frequency generator and a 2-cm active tip antenna. RF ablations were performed with a bipolar RF system with 2- and 3-cm active tip electrodes. Tissue temperatures were continuously monitored during ablation. Results: The mean short-axis diameters of the coagulation zones were 1.34 {+-} 0.14, 1.45 {+-} 0.13, and 1.74 {+-} 0.11 cm for MW ablation at outputs of 25W, 35W, and 45W. For RF ablation, the corresponding values were 1.16 {+-} 0.09 and 1.26 {+-} 0.14 cm with electrodes having 2- and 3-cm active tips, respectively. The mean coagulation volumes were 2.27 {+-} 0.65, 2.85 {+-} 0.72, and 4.45 {+-} 0.47 cm{sup 3} for MW ablation at outputs of 25W, 35W, and 45W and 1.18 {+-} 0.30 and 2.29 {+-} 0.55 cm{sup 3} got RF ablation with 2- and 3-cm electrodes, respectively. MW ablations at 35W and 45W achieved significantly longer short-axis diameters than RF ablations (P < 0.05). The highest tissue temperature was achieved with MW ablation at 45W (P < 0.05). On histological examination, the extent of the ablation zone in MW ablations was less affected by tissue heterogeneity than that in RF ablations. Conclusion: MW ablation appears to be advantageous with respect to the volume of ablation and the shape of the margin of necrosis compared with RF ablation in an ex vivo bovine udder.

  14. The mechanism of thin film Si nanomachining using femtosecond laser pulses

    E-Print Network [OSTI]

    Jia, Jimmy Yi-Jie, 1980-

    2004-01-01T23:59:59.000Z

    Femtosecond (fs) laser ablation has been the subject of intense recent research. The pulse time ('width') is shorter than the electronic relaxation time, resulting in a decoupling of the period of laser illumination and ...

  15. X-ray ablation measurements and modeling for ICF applications

    SciTech Connect (OSTI)

    Anderson, A.T.

    1996-09-01T23:59:59.000Z

    X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and hohlraum wall thickness are also described. Experiments have been conducted at the Nova laser on the effects of relevant x-ray fluences on various materials. The response was diagnosed using post-shot examinations of the surfaces with scanning electron microscope and atomic force microscope instruments. Judgments were made about the dominant removal mechanisms for each material. Measurements of removal depths were made to provide data for the modeling. The finite difference ablation code developed here (ABLATOR) combines the thermomechanical response of materials to x-rays with models of various removal mechanisms. The former aspect refers to energy deposition in such small characteristic depths ({approx} micron) that thermal conduction and hydrodynamic motion are significant effects on the nanosecond time scale. The material removal models use the resulting time histories of temperature and pressure-profiles, along with ancillary local conditions, to predict rates of surface vaporization and the onset of conditions that would lead to spallation.

  16. Characterization of tracked radiofrequency ablation in phantom

    SciTech Connect (OSTI)

    Chen, Chun-Cheng R.; Miga, Michael I.; Galloway, Robert L. [Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37235 (United States)

    2007-10-15T23:59:59.000Z

    In radiofrequency ablation (RFA), successful therapy requires accurate, image-guided placement of the ablation device in a location selected by a predictive treatment plan. Current planning methods rely on geometric models of ablations that are not sensitive to underlying physical processes in RFA. Implementing plans based on computational models of RFA with image-guided techniques, however, has not been well characterized. To study the use of computational models of RFA in planning needle placement, this work compared ablations performed with an optically tracked RFA device with corresponding models of the ablations. The calibration of the tracked device allowed the positions of distal features of the device, particularly the tips of the needle electrodes, to be determined to within 1.4{+-}0.6 mm of uncertainty. Ablations were then performed using the tracked device in a phantom system based on an agarose-albumin mixture. Images of the sliced phantom obtained from the ablation experiments were then compared with the predictions of a bioheat transfer model of RFA, which used the positional data of the tracked device obtained during ablation. The model was demonstrated to predict 90% of imaged pixels classified as being ablated. The discrepancies between model predictions and observations were analyzed and attributed to needle tracking inaccuracy as well as to uncertainties in model parameters. The results suggest the feasibility of using finite element modeling to plan ablations with predictable outcomes when implemented using tracked RFA.

  17. Nanometer-scale ablation using focused, coherent extreme ultraviolet/soft x-ray light

    DOE Patents [OSTI]

    Menoni, Carmen S. (Fort Collins, CO); Rocca, Jorge J. (Fort Collins, CO); Vaschenko, Georgiy (San Diego, CA); Bloom, Scott (Encinitas, CA); Anderson, Erik H. (El Cerrito, CA); Chao, Weilun (El Cerrito, CA); Hemberg, Oscar (Stockholm, SE)

    2011-04-26T23:59:59.000Z

    Ablation of holes having diameters as small as 82 nm and having clean walls was obtained in a poly(methyl methacrylate) on a silicon substrate by focusing pulses from a Ne-like Ar, 46.9 nm wavelength, capillary-discharge laser using a freestanding Fresnel zone plate diffracting into third order is described. Spectroscopic analysis of light from the ablation has also been performed. These results demonstrate the use of focused coherent EUV/SXR light for the direct nanoscale patterning of materials.

  18. androgen ablation therapy: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Shirley 15 ImageGuided Ex vivo Liver Ablation by Unfocused Ultrasound using Passive Cavitation Detection Engineering Websites Summary: Thermal ablation is widely used for...

  19. Kinetic-energy-angle differential distribution of photofragments in multiphoton above-threshold dissociation of D{sub 2}{sup +} by linearly polarized 400-nm intense laser fields: Effects of highly excited electronic states

    SciTech Connect (OSTI)

    Khan, Basir Ahamed; Saha, Samir; Bhattacharyya, S. S. [Atomic and Molecular Physics Section, Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

    2006-02-15T23:59:59.000Z

    We have performed a detailed calculation of the double-differential angular-kinetic-energy distribution of photofragments in above threshold dissociation (ATD) of D{sub 2}{sup +} from initial vibrational-rotational levels v{sub i}=4,5 and J{sub i}=0,1 in an intense linearly polarized laser field of wavelength 400 nm and intensity 3x10{sup 13} W/cm{sup 2}. The calculation used a time-independent close-coupling (CC) formalism with eight (ten) electronic states included in the basis-set expansion of the molecular wave function. The molecular electronic states included, apart from the two lowest 1s{sigma}{sub g} and 2p{sigma}{sub u} states, were 2p{pi}{sub u}{sup {+-}}, 2s{sigma}{sub g}, 3p{sigma}{sub u}, 3d{sigma}{sub g}, 3d{pi}{sub g}{sup {+-}}, and 4f{sigma}{sub u}. All the higher electronic states dissociate to the atomic state D(2l). A sufficient number of photon absorption channels, n=0-7, and molecular rotational quantum numbers J=0-11 were taken into account to ensure the convergence of the multiphoton ATD probability. Altogether 198 coupled channels had to be considered in the calculation. The calculations reveal signatures of significant ejection of the photodissociation fragments away from the laser polarization direction due to the inclusion of the higher excited electronic states. The ratio of the photofragments perpendicular to and along the polarization axis shows good quantitative agreement with the experimental result. The angular distributions show considerable structures depending on the relative kinetic energies of the photofragments, and the fragments with different kinetic energies show peaks at different dissociation angles.

  20. Laser-plasma instabilities in large plasmas irradiated at 1. 06. mu. m and the wavelength scaling of the absorption, hot-electron production, ablation pressure for 1. 06-, 0. 53-, and 0. 35-. mu. m light

    SciTech Connect (OSTI)

    Phillion, D.W.; Campbell, E.M.; Turner, R.E.

    1982-01-01T23:59:59.000Z

    Plasmas were created by exploding 7000 A thick CH foils at the irradiation conditions: 1.064 ..mu..m, 3 kJ, 2.5 x 10/sup 15/ W/cm/sup 2/, 900 ps FWHM, 400 ..mu..m spot diameter. Ten percent of the laser energy appeared as Raman light and 0.04% as 3..omega../sub 0//2 light. The 3..omega../sub 0//2 light and the 30-70 keV X rays occurred simultaneouly at t=-120/sup +50//sub -//sub 200/ psec and lasted only 300 psec FWHM. The foil was calculated to explode to n/sub c/4 at t=-300 psec. The spectrum and angular distribution of the Raman light were also measured. Time-resolved spectral measurements have been made in experiments with 5320 A laser light in a 600-900 psec FWHM pulse. The scaling of the 3..omega../sub 0//2 light with both the laser spot size and pulse length has been studied.

  1. Beam current controller for laser ion source

    DOE Patents [OSTI]

    Okamura, Masahiro

    2014-10-28T23:59:59.000Z

    The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

  2. Ultrashort-pulse laser generated nanoparticles of energetic materials

    DOE Patents [OSTI]

    Welle, Eric J. (Niceville, NM); Tappan, Alexander S. (Albuquerque, NM); Palmer, Jeremy A. (Albuquerque, NM)

    2010-08-03T23:59:59.000Z

    A process for generating nanoscale particles of energetic materials, such as explosive materials, using ultrashort-pulse laser irradiation. The use of ultrashort laser pulses in embodiments of this invention enables one to generate particles by laser ablation that retain the chemical identity of the starting material while avoiding ignition, deflagration, and detonation of the explosive material.

  3. Method of defining features on materials with a femtosecond laser

    DOE Patents [OSTI]

    Roos, Edward Victor (Los Altos, CA); Roeske, Franklin (Livermore, CA); Lee, Ronald S. (Livermore, CA); Benterou, Jerry J. (Livermore, CA)

    2006-05-23T23:59:59.000Z

    The invention relates to a pulsed laser ablation method of metals and/or dielectric films from the surface of a wafer, printed circuit board or a hybrid substrate. By utilizing a high-energy ultra-short pulses of laser light, such a method can be used to manufacture electronic circuits and/or electro-mechanical assemblies without affecting the material adjacent to the ablation zone.

  4. Laser-direct-driven quasi-isentropic experiments on aluminum

    SciTech Connect (OSTI)

    Xue, Quanxi, E-mail: quanxixue@163.com [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); State Key Laboratory of Laser Interaction with Matter, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Wang, Zhebin; Jiang, Shaoen, E-mail: jiangshn@vip.sina.com; Wang, Feng [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Ye, Xisheng; Liu, Jingru [State Key Laboratory of Laser Interaction with Matter, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

    2014-07-15T23:59:59.000Z

    Laser-direct-driven ramp compression experiments were performed on long temporally shaped laser pulses based on an analytical isentropic compression model. Upper pressure limits, the ablation pressure scaling law, and stress-density curves were studied. The validity of the analytical model used, the ablation pressure scaling law, and the phenomena of missing line-imaging velocity interferometer (VISAR) fringes in the experimental results are discussed.

  5. Review of multi-dimensional large-scale kinetic simulation and physics validation of ion acceleration in relativistic laser-matter interaction

    SciTech Connect (OSTI)

    Wu, Hui-Chun [Los Alamos National Laboratory; Hegelich, B.M. [Los Alamos National Laboratory; Fernandez, J.C. [Los Alamos National Laboratory; Shah, R.C. [Los Alamos National Laboratory; Palaniyappan, S. [Los Alamos National Laboratory; Jung, D. [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory; Albright, B.J. [Los Alamos National Laboratory; Bowers, K. [Guest Scientist of XCP-6; Huang, C. [Los Alamos National Laboratory; Kwan, T.J. [Los Alamos National Laboratory

    2012-06-19T23:59:59.000Z

    Two new experimental technologies enabled realization of Break-out afterburner (BOA) - High quality Trident laser and free-standing C nm-targets. VPIC is an powerful tool for fundamental research of relativistic laser-matter interaction. Predictions from VPIC are validated - Novel BOA and Solitary ion acceleration mechanisms. VPIC is a fully explicit Particle In Cell (PIC) code: models plasma as billions of macro-particles moving on a computational mesh. VPIC particle advance (which typically dominates computation) has been optimized extensively for many different supercomputers. Laser-driven ions lead to realization promising applications - Ion-based fast ignition; active interrogation, hadron therapy.

  6. Formation of Micro and Nano Structures Using VUV 157 nm Laser Radiation

    SciTech Connect (OSTI)

    Walton, C. D.; Cockcroft, S. [Physics, Department of Physical Sciences, University of Hull, HU6 7RX (United Kingdom)

    2010-10-08T23:59:59.000Z

    We report on laser ablation experiments on micro and nano size composite structures. The surface of CR-39 and polycarbonate has been intentionally seeded with silicon carbide and silver nanowires and subsequently laser irradiated at a wavelength of 157 nm. We show scanning electron micrograph images of prismatic and conical structures produced by laser ablation and discuss a shape transformation from a prismatic to a conical structure.

  7. Experimental and theoretical studies of particle generation afterlaser ablation of copper with background gas at atmosphericpressure

    SciTech Connect (OSTI)

    Wen, Sy-Bor; Mao, Xianglei; Greif, Ralph; Russo, Richard E.

    2007-05-31T23:59:59.000Z

    Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the condensed aerosol plume were observed in two background gases, helium and argon. The primary particle shape and size distribution were measured using a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a differential mobility analyzer (DMA). The gas dynamics simulation included nucleation and coagulation within the vapor plume, heat and mass transfer from the vapor plume to the background gas, and heat transfer to the sample. The experimental data and the calculated evolution of the shape of the vapor plume showed the same trend for the spatial distribution of the condensed particles in both background gases. The simulated particle size distribution also qualitatively agreed with the experimental data. It was determined that the laser energy, the physical properties of the background gas (conductivity, diffusivity and viscosity), and the shape of the ablation system (ablation chamber and the layout of the sample) have strong effects on the condensation process and the subsequent sizes, shapes and degree of aggregation of the particles.

  8. Kinetics of Silica Polymerization

    E-Print Network [OSTI]

    Weres, Oleh

    2011-01-01T23:59:59.000Z

    see S . ) It is the kinetic expression of the increase Therate is in part the kinetic expression of. the reducedrates calculated using kinetic expressions given in Chapter

  9. Factors Limiting Complete Tumor Ablation by Radiofrequency Ablation

    SciTech Connect (OSTI)

    Paulet, Erwan, E-mail: erwanpaulet@yahoo.fr; Aube, Christophe [University Hospital Angers, Department of Radiology (France); Pessaux, Patrick [University Hospital Angers, Department of Visceral Surgery (France); Lebigot, Jerome [University Hospital Angers, Department of Radiology (France); Lhermitte, Emilie [University Hospital Angers, Department of Visceral Surgery (France); Oberti, Frederic [University Hospital Angers, Department of Hepato-Gastroenterology (France); Ponthieux, Anne [University Hospital Angers, Clinical Research Center (France); Cales, Paul [University Hospital Angers, Department of Hepato-Gastroenterology (France); Ridereau-Zins, Catherine [University Hospital Angers, Department of Radiology (France); Pereira, Philippe L. [Eberhard-Karls University, Department of Diagnostic Radiology (Germany)

    2008-01-15T23:59:59.000Z

    The purpose of this study was to determine radiological or physical factors to predict the risk of residual mass or local recurrence of primary and secondary hepatic tumors treated by radiofrequency ablation (RFA). Eighty-two patients, with 146 lesions (80 hepatocellular carcinomas, 66 metastases), were treated by RFA. Morphological parameters of the lesions included size, location, number, ultrasound echogenicity, computed tomography density, and magnetic resonance signal intensity were obtained before and after treatment. Parameters of the generator were recorded during radiofrequency application. The recurrence-free group was statistically compared to the recurrence and residual mass groups on all these parameters. Twenty residual masses were detected. Twenty-nine lesions recurred after a mean follow-up of 18 months. Size was a predictive parameter. Patients' sex and age and the echogenicity and density of lesions were significantly different for the recurrence and residual mass groups compared to the recurrence-free group (p < 0.05). The presence of an enhanced ring on the magnetic resonance control was more frequent in the recurrence and residual mass groups. In the group of patients with residual lesions, analysis of physical parameters showed a significant increase (p < 0.05) in the time necessary for the temperature to rise. In conclusion, this study confirms risk factors of recurrence such as the size of the tumor and emphasizes other factors such as a posttreatment enhanced ring and an increase in the time necessary for the rise in temperature. These factors should be taken into consideration when performing RFA and during follow-up.

  10. Pulsed laser deposition of epitaxial BeO thin films on sapphire and SrTiO{sub 3}

    SciTech Connect (OSTI)

    Peltier, Thomas; Takahashi, Ryota; Lippmaa, Mikk, E-mail: mlippmaa@issp.u-tokyo.ac.jp [Institute for Solid State Physics, University of Tokyo, Chiba 277-8581 (Japan)

    2014-06-09T23:59:59.000Z

    Epitaxial beryllia thin films were grown by pulsed laser deposition on Al{sub 2}O{sub 3}(001) and SrTiO{sub 3}(111) substrates. Nearly relaxed epitaxial films were obtained on both substrates at growth temperatures of up to about 600?°C. Crystalline films with expanded lattice parameters were obtained even at room temperature. The maximum growth temperature was limited by a loss of beryllium from the film surface. The volatility of beryllium appeared to be caused by the slow oxidation kinetics at the film surface and the re-sputtering effect of high-energy Be and BeO species in the ablation plume. Time-of-flight plume composition analysis suggested that the target surface became Be metal rich at low oxygen pressures, reducing the growth rate of beryllia films.

  11. Optical coherence and beamspread in ultrafast-laser pulsetrain-burst hole drilling

    E-Print Network [OSTI]

    Marjoribanks, Robin S.

    advantages over single-pulse laser processing of materials and biological tissues. Ultrafast lasers are often material, as is sometimes the case for nanosecond-pulse ablation; further, pulsetrain-bursts of ultrafast of ultrafast laser pulses, at a repetition rate of 1 MHz or greater, is less likely to leave cracks or residual

  12. Boston University User Fee Structure for ICP-ES, ICP-MS and Laser Labs

    E-Print Network [OSTI]

    Hutyra, Lucy R.

    Cost per sample by laser ablation includes three spots on a sample plus an additional three spotsBoston University User Fee Structure for ICP-ES, ICP-MS and Laser Labs The Department of Earth come to BU and digest their samples in our labs with sufficient training. Laser-ICP-MS cost per sample

  13. Journal of Applied Physics 104,093504 (2008) Picosecond laser structuration under high pressures

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    2008-01-01T23:59:59.000Z

    A research on ultra-short laser modification of materials has been a subject of numerous studies last two. The main effect is specific to the ambient gas and laser pulse duration in the ablation regime: whenJournal of Applied Physics 104,093504 (2008) Picosecond laser structuration under high pressures

  14. Formation of nanoparticles by short and ultra-short laser pulses K. Gouriet*a

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Formation of nanoparticles by short and ultra-short laser pulses K. Gouriet*a , T. E. Itinaa , S. Noëla , J. Hermanna , M. Sentisa , and L. Zhigileib a Laboratory of Lasers, Plasmas and Photonics simulation Monte Carlo (DSMC) computational study of laser ablation plume evolution. The first process

  15. Role of Cavitation in Bulk Ultrasound Ablation: A Histologic Study

    E-Print Network [OSTI]

    Mast, T. Douglas

    Role of Cavitation in Bulk Ultrasound Ablation: A Histologic Study Chandra Priya Karunakaran, Mark of Cincinnati, Cincinnati, Ohio Abstract. The role of cavitation in bulk ultrasound ablation has been evaluated-ablate probe at 31 W/cm2 for 20 minutes under normal and elevated ambient pressures. A 1 MHz passive cavitation

  16. Process for laser machining and surface treatment

    DOE Patents [OSTI]

    Neil, George R.; Shinn, Michelle D.

    2004-10-26T23:59:59.000Z

    An improved method and apparatus increasing the accuracy and reducing the time required to machine materials, surface treat materials, and allow better control of defects such as particulates in pulsed laser deposition. The speed and quality of machining is improved by combining an ultrashort pulsed laser at high average power with a continuous wave laser. The ultrashort pulsed laser provides an initial ultrashort pulse, on the order of several hundred femtoseconds, to stimulate an electron avalanche in the target material. Coincident with the ultrashort pulse or shortly after it, a pulse from a continuous wave laser is applied to the target. The micromachining method and apparatus creates an initial ultrashort laser pulse to ignite the ablation followed by a longer laser pulse to sustain and enlarge on the ablation effect launched in the initial pulse. The pulse pairs are repeated at a high pulse repetition frequency and as often as desired to produce the desired micromachining effect. The micromachining method enables a lower threshold for ablation, provides more deterministic damage, minimizes the heat affected zone, minimizes cracking or melting, and reduces the time involved to create the desired machining effect.

  17. Isotopically Enriched Films and Nanostructures by Ultrafast Pulsed Laser Deposition

    SciTech Connect (OSTI)

    Peter Pronko

    2004-12-13T23:59:59.000Z

    This project involved a systematic study to apply newly discovered isotopic enrichment effects in laser ablation plumes to the fabrication of isotopically engineered thin films, superlattices, and nanostructures. The approach to this program involved using ultrafast lasers as a method for generating ablated plasmas that have preferentially structured isotopic content in the body of the ablation plasma plumes. In examining these results we have attempted to interpret the observations in terms of a plasma centrifuge process that is driven by the internal electro-magnetic fields of the plasma itself. The research plan involved studying the following phenomena in regard to the ablation plume and the isotopic mass distribution within it: (1) Test basic equations of steady state centrifugal motion in the ablation plasma. (2) Investigate angular distribution of ions in the ablation plasmas. (3) Examine interactions of plasma ions with self-generated magnetic fields. (3) Investigate ion to neutral ratios in the ablation plasmas. (5) Test concepts of plasma pumping. (6) Fabricate isotopically enriched nanostructures.

  18. Kinetics of small single particle combustion of zirconium alloy

    SciTech Connect (OSTI)

    Wei Haoyan; Yoo, Choong-Shik [Department of Chemistry and Institute for Shock Physics, Washington State University, Pullman, Washington 99164-2816 (United States)

    2012-01-15T23:59:59.000Z

    We present quantitative kinetic information regarding small, 1-10 {mu}m in diameter, single particle combustion of Zr-rich metal alloy foils subjected to either mechanical impacts or laser-ablation. The lights from combustion of metal fragments were recorded on a high-speed camera. The particle size was determined by the motion analysis of individual particle trajectory based on an aerodynamic drag law and further verified by the microstructure and chemical composition analysis of recovered post-burn particles. The measured particle sizes show a log-normal distribution centered at around 3.1 {mu}m in diameter, and the composition of recovered particles is that of fully oxidized ZrO{sub 2}. The temperature evolution of each particle along the space/time-trajectory is determined based on the thermal emission from combustion using a single-color photographic spectro-pyrometry. The result indicates that the particle has reached the maximum combustion temperature of 4000 K, well beyond the melting temperature of ZrO{sub 2}, and undergone the solidification of molten ZrO{sub 2} during the cooling stage. It also shows that the maximum combustion temperature decreases linearly with increasing the particle diameter, following the correlation t aD{sup 1.5-1.8} between the burn time (t) and the particle diameter (D). Combining the particle size, the burn time, and the particle temperature, both temperature and mass burn rates are obtained as a function of particle size. As the particle size increases, the temperature burn rate decreases, whereas the mass burn rate goes in the opposite direction.

  19. High density laser-driven target

    DOE Patents [OSTI]

    Lindl, John D. (San Ramon, CA)

    1981-01-01T23:59:59.000Z

    A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

  20. Method for laser induced isotope enrichment

    DOE Patents [OSTI]

    Pronko, Peter P.; Vanrompay, Paul A.; Zhang, Zhiyu

    2004-09-07T23:59:59.000Z

    Methods for separating isotopes or chemical species of an element and causing enrichment of a desired isotope or chemical species of an element utilizing laser ablation plasmas to modify or fabricate a material containing such isotopes or chemical species are provided. This invention may be used for a wide variety of materials which contain elements having different isotopes or chemical species.

  1. Laser pulse detector

    DOE Patents [OSTI]

    Mashburn, Douglas N. (Knoxville, TN); Akerman, M. Alfred (Knoxville, TN)

    1981-01-01T23:59:59.000Z

    A laser pulse detector is provided which is small and inexpensive and has the capability of detecting laser light of any wavelength with fast response (less than 5 nanoseconds rise time). The laser beam is focused onto the receiving end of a graphite rod coaxially mounted within a close-fitting conductive, open-end cylindrical housing so that ablation and electric field breakdown of the resulting plasma occurs due to a bias potential applied between the graphite rod and housing. The pulse produced by the breakdown is transmitted through a matched impedance coaxial cable to a recording device. The cable is connected with its central lead to the graphite rod and its outer conductor to the housing.

  2. Kinetic studies of isoprene reactions with hydroxyl and chlorine radicals

    E-Print Network [OSTI]

    Suh, Inseon

    2000-01-01T23:59:59.000Z

    Kinetic studies of the isoprene oxidation reactions initiated by the hydroxyl radical OH and the chlorine atom Cl have been investigated using a fast-flow reactor in conjunction with chemical ionization mass spectrometry (CIMS) and using laser...

  3. ablative fractional lasers: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    from zinc nanoclasters size of several nanometers to ZnO fractal aggregates (FA) size up to hundreds of nanometers. Determinants of this process are the average power and an...

  4. The influence of ambient medium density on laser ablation processes

    SciTech Connect (OSTI)

    Kilgo, M.M. III

    1995-11-01T23:59:59.000Z

    Interest in high flux transport processes has grown in recent years along with the ability and need to manipulate systems with microscopic length and time scales. These systems present unique engineering challenges. Because the time and length scales associated with these problems are very small, assumptions of local equilibrium, physical and mathematical smoothness of boundaries and the unambiguous definition of thermodynamic fields can not be automatically made, even though they may ultimately be acceptable. Furthermore, the observations are made on macroscopic or integrated scales. The large difference in scales between the temporal evolution of the process and the observation requires careful consideration of the claims made regarding the system`s microscopic, temporal behavior. In particular, consistency of a proposed model with observed results does not guarantee uniqueness, or predictive accuracy for the model. For these reasons, microscale heat transfer systems demand a careful consideration of the framework within which the experimentation and analysis are conducted.

  5. Apparatus for the laser ablative synthesis of carbon nanotubes

    DOE Patents [OSTI]

    Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA)

    2010-02-16T23:59:59.000Z

    An RF-induction heated side-pumped synthesis chamber for the production of carbon nanotubes. Such an apparatus, while capable of producing large volumes of carbon nanotubes, concurrently provides a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization.

  6. Improvements to Laser Ablation-Inductively Coupled Plasma-Mass...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of trace element evidence to different materials (e.g., glass panes, metals, plastics, tapes) of forensic interest. Short validation studies to investigate the potential...

  7. Apparatus for the Laser Ablative Synthesis of Carbon Nanotubes - Energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProductsAlternative FuelsSanta3 Tableimpurity

  8. Application of copper vapour lasers for controlling activity of uranium isotopes

    SciTech Connect (OSTI)

    Barmina, E V; Sukhov, I A; Lepekhin, N M; Priseko, Yu S; Filippov, V G; Simakin, Aleksandr V; Shafeev, Georgii A

    2013-06-30T23:59:59.000Z

    Beryllium nanoparticles are generated upon ablation of a beryllium target in water by a copper vapour laser. The average size of single crystalline nanoparticles is 12 nm. Ablation of a beryllium target in aqueous solutions of uranyl chloride leads to a significant (up to 50 %) decrease in the gamma activity of radionuclides of the uranium-238 and uranium-235 series. Data on the recovery of the gamma activity of these nuclides to new steady-state values after laser irradiation are obtained. The possibility of application of copper vapour lasers for radioactive waste deactivation is discussed. (laser applications and other topics in quantum electronics)

  9. Cryogenic THD and DT layer implosions with high density carbon ablators in near-vacuum hohlraums

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Meezan, N. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Berzak Hopkins, L. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000291875667); Le Pape, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Divol, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); MacKinnon, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Döppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ho, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Khan, S. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ma, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Milovich, J. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pak, A. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ross, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thomas, C. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Benedetti, L. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bradley, D. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Celliers, P. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Clark, D. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000272137538); Field, J. E. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA; Haan, S. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000184045131); Izumi, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kyrala, G. A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moody, J. D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA; Patel, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ralph, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rygg, J. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sepke, S. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spears, B. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tommasini, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Town, R. P. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Biener, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bionta, R. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bond, E. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Caggiano, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Eckart, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gatu Johnson, M. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Grim, G. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hamza, A. V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hartouni, E. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000198694351); Hatarik, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hoover, D. E. [General Atomics, San Diego, CA (United States)] (ORCID:0000000195652551); Kilkenny, J. D. [General Atomics, San Diego, CA (United States); Kozioziemski, B. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kroll, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McNaney, J. M. [General Atomics, San Diego, CA (United States); Nikroo, A. [General Atomics, San Diego, CA (United States); Sayre, D. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-01T23:59:59.000Z

    High Density Carbon (HDC or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of et al., Phys. Plasmas 16, 041006 (2009)] culminated in a DT layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a THD layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 x 10¹? neutrons, 40% of the 1D simulated yield.

  10. Plume dynamics and shielding characteristics of nanosecond scale multiple pulse in carbon ablation

    SciTech Connect (OSTI)

    Pathak, Kedar; Povitsky, Alex [Department of Mechanical Engineering, University of Akron, Akron, Ohio 44325-3903 (United States)

    2008-12-01T23:59:59.000Z

    The behavior of ablated plumes produced by nanosecond scale multiple laser pulses typical for carbon ablation is studied in order to understand the plume expansion dynamics and shielding effect of plume with special interest to ionization of plumes. The patterns of a planar plume (typical for channel cutting) and an axisymmetric plume (typical for hole drilling) appear to be quite different. Ionization in carbon plume is estimated using the Saha equation. An iterative procedure is developed to determine the local equilibrium temperature affected by ionization. It is shown that though shielding due to the presence of ionized particles in carbon plume is small, the effect of ionization on plume temperature can be considerable. Shielding effect is calculated for laser pulses with different time intervals between pulses. The effects of high temperature and low density of plume are conflicting and cause shielding behavior to be nonmonotonic. It is shown that the nonmonotonic dependence of the delivered laser energy, the pulse number, and the difference in shielding characteristics between planar and axisymmetric formulations increase with the time duration between two consecutive pulses.

  11. Cryogenic THD and DT layer implosions with high density carbon ablators in near-vacuum hohlraums

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Meezan, N. B.; Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; et al

    2015-06-01T23:59:59.000Z

    High Density Carbon (HDC or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of et al., Phys. Plasmas 16, 041006 (2009)] culminated in a DT layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a THD layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightlymore »oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 x 10¹? neutrons, 40% of the 1D simulated yield.« less

  12. Cross-sectional transmission electron microscopy study of femtosecond laser-irradiated selenium-doped 'black' silicon

    E-Print Network [OSTI]

    Reading, Arthur H. (Arthur Henry)

    2009-01-01T23:59:59.000Z

    'Black silicon' refers to silicon that has been treated in a laser-ablation process to incorporate large amounts of chalcogen dopants. The material has been found to have greatly increased absorbance of visible and infared ...

  13. Short pulse laser-induced optical damage and fracto-emission of amorphous, diamond-like carbon

    SciTech Connect (OSTI)

    SOKOLOWSKI-TINTEN,K.; VON DER LINDE,D.; SIEGAL,MICHAEL P.; OVERMYER,DONALD L.

    2000-02-07T23:59:59.000Z

    Short pulse laser damage and ablation of amorphous, diamond-like carbon films is investigated. Material removal is due to fracture of the film and ejection of large fragments, which exhibit a broadband emission of microsecond duration.

  14. Influence of oxygen pressure and aging on LaAlO{sub 3} films grown by pulsed laser deposition on SrTiO{sub 3} substrates

    SciTech Connect (OSTI)

    Park, Jihwey; Aeppli, Gabriel [London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom); Soh, Yeong-Ah, E-mail: yeongahsoh@gmail.com [London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom); Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); David, Adrian; Lin, Weinan [Division of Physics and Applied Physics, Nanyang Technological University, Singapore 637371 (Singapore); Wu, Tom [Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

    2014-02-24T23:59:59.000Z

    The crystal structures of LaAlO{sub 3} films grown by pulsed laser deposition on SrTiO{sub 3} substrates at oxygen pressure of 10{sup ?3} millibars or 10{sup ?5} millibars, where kinetics of ablated species hardly depend on oxygen background pressure, are compared. Our results show that the interface between LaAlO{sub 3} and SrTiO{sub 3} is sharper when the oxygen pressure is lower. Over time, the formation of various crystalline phases is observed while the crystalline thickness of the LaAlO{sub 3} layer remains unchanged. X-ray scattering as well as atomic force microscopy measurements indicate three-dimensional growth of such phases, which appear to be fed from an amorphous capping layer present in as-grown samples.

  15. High precision analysis of all four stable isotopes of sulfur S) at nanomole levels using a laser fluorination

    E-Print Network [OSTI]

    Long, Bernard

    compositions. This methodology increases the spatial resolution of the laser ablation in situ analysis) at nanomole levels using a laser fluorination isotope-ratio-monitoring gas chromatography­mass spectrometry.V. All rights reserved. Keywords: S-33; S-36; Sulfur isotope; Laser; Isotope analysis; Continuous flow

  16. Dynamics of cavitation bubble induced by 193 nm ArF excimer laser in concentrated sodium chloride solutions

    E-Print Network [OSTI]

    Palanker, Daniel

    of pulsed lasers for ablation, drilling, and cutting of soft tissues in liquid environments are accompaniedDynamics of cavitation bubble induced by 193 nm ArF excimer laser in concentrated sodium chloride solutions Igor Turovets and Daniel Palanker Laser Center, Hadassah University Hospital, P.O. Box 12000

  17. ablation particle beam: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    LASer in Hamburg) provides ultra-intense femtosecond radiation and laser optics: UV, XUV, and X-ray lasers; (140.2600) Lasers and laser optics: Free electron lasers;...

  18. ablative thermal protection: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    assembly methodology and material test performance was documented 12 Measurements of Cavitation Dose, Echogenicity, and Temperature during Ultrasound Ablation Biology and Medicine...

  19. Ion Acceleration by Short Chirped Laser Pulses

    E-Print Network [OSTI]

    Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltán

    2015-01-01T23:59:59.000Z

    Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

  20. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    SciTech Connect (OSTI)

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Lemm, G.; Hohenstein, E. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany); Bellemann, N.; Stampfl, U. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Goezen, A. S.; Rassweiler, J. [Clinic for Urology, SLK Kliniken Heilbronn GmbH (Germany); Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P. L. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany)

    2013-06-15T23:59:59.000Z

    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  1. Casingless down-hole for sealing an ablation volume and obtaining a sample for analysis

    DOE Patents [OSTI]

    Noble, Donald T. (Ames, IA); Braymen, Steven D. (Ames, IA); Anderson, Marvin S. (Ames, IA)

    1996-10-01T23:59:59.000Z

    A casing-less down hole sampling system for acquiring a subsurface sample for analysis using an inductively coupled plasma system is disclosed. The system includes a probe which is pushed into the formation to be analyzed using a hydraulic ram system. The probe includes a detachable tip member which has a soil point mad a barb, with the soil point aiding the penetration of the earth, and the barb causing the tip member to disengage from the probe and remain in the formation when the probe is pulled up. The probe is forced into the formation to be tested, and then pulled up slightly, to disengage the tip member and expose a column of the subsurface formation to be tested. An instrumentation tube mounted in the probe is then extended outward from the probe to longitudinally extend into the exposed column. A balloon seal mounted on the end of the instrumentation tube allows the bottom of the column to be sealed. A source of laser radiation is emitted from the instrumentation tube to ablate a sample from the exposed column. The instrumentation tube can be rotated in the probe to sweep the laser source across the surface of the exposed column. An aerosol transport system carries the ablated sample from the probe to the surface for testing in an inductively coupled plasma system. By testing at various levels in the down-hole as the probe is extracted from the soil, a profile of the subsurface formation may be obtained.

  2. Casingless down-hole for sealing an ablation volume and obtaining a sample for analysis

    DOE Patents [OSTI]

    Noble, D.T.; Braymen, S.D.; Anderson, M.S.

    1996-10-01T23:59:59.000Z

    A casing-less down hole sampling system for acquiring a subsurface sample for analysis using an inductively coupled plasma system is disclosed. The system includes a probe which is pushed into the formation to be analyzed using a hydraulic ram system. The probe includes a detachable tip member which has a soil point and a barb, with the soil point aiding the penetration of the earth, and the barb causing the tip member to disengage from the probe and remain in the formation when the probe is pulled up. The probe is forced into the formation to be tested, and then pulled up slightly, to disengage the tip member and expose a column of the subsurface formation to be tested. An instrumentation tube mounted in the probe is then extended outward from the probe to longitudinally extend into the exposed column. A balloon seal mounted on the end of the instrumentation tube allows the bottom of the column to be sealed. A source of laser radiation is emitted from the instrumentation tube to ablate a sample from the exposed column. The instrumentation tube can be rotated in the probe to sweep the laser source across the surface of the exposed column. An aerosol transport system carries the ablated sample from the probe to the surface for testing in an inductively coupled plasma system. By testing at various levels in the down-hole as the probe is extracted from the soil, a profile of the subsurface formation may be obtained. 9 figs.

  3. Plasmadynamics and ionization kinetics of thermionic energy conversion

    SciTech Connect (OSTI)

    Lawless, J.L. Jr.; Lam, S.H.

    1982-02-01T23:59:59.000Z

    To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. To combine the analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. It is capable of solving for both unsteady and steady thermionic converter behavior including possible laser ionization enhancement or atomic recombination lasing. A proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed. (WHK)

  4. Laser Beam Profile Influence on LIBS Analytical Capabilities: Single vs. Multimode Beam

    E-Print Network [OSTI]

    Lednev, Vasily N; Bunkin, Alexey F

    2013-01-01T23:59:59.000Z

    Single vs. multimode laser beams have been compared for laser ablation on steel samples. Laser plasma properties and analytical capabilities (precision, limit of detection) were used as key parameters for comparison. Peak fluence at focal spot has been observed to be higher for Gaussian beam despite ~14-fold lower pulse energy. A comparison of Gaussian and multimode beams with equal energy was carried out in order to estimate influence of beam profile only. Single mode lasing (Gaussian beam) results in better reproducibility of analytical signals compared to multimode lasing while laser energy reproducibility was the same for both cases. Precision improvements were attributed to more stable laser ablation due to better reproducibility of beam profile fluence at laser spot. Plasma temperature and electron density were higher for Gaussian laser beam. Calibration curves were obtained for four elements under study (Cr, Mn, Si, Cu). Two sampling (drilling and scanning procedures) and two optical detection schemes ...

  5. The so-called dry laser cleaning governed by humidity at the nanometer scale Ph. Delaporte,

    E-Print Network [OSTI]

    Boyer, Edmond

    Cedex 9, France O.H. Pakarinen and A.S. Foster Laboratory of Physics, Helsinki University of Technology two laser-energy dependent cleaning regimes by time-of-flight particle-scattering diagnostics. For the higher energies, the ejection of particles is produced by nanoscale ablation due to the laser field

  6. Laser Physics, Vol. 12, No. 2, 2002, pp. 292299. Original Text Copyright 2002 by Astro, Ltd.

    E-Print Network [OSTI]

    Shalaev, Vladimir M.

    of advantages in generating of ultra-short pulses. Such films can simultaneously provide sub-wavelength (down be prepared by deposition of metal onto a dielectric substrate. This can be done by laser ablation, thermal292 Laser Physics, Vol. 12, No. 2, 2002, pp. 292­299. Original Text Copyright © 2002 by Astro, Ltd

  7. Emission characteristics and dynamics of C2 from laser produced graphite plasma

    E-Print Network [OSTI]

    Harilal, S. S.

    Emission characteristics and dynamics of C2 from laser produced graphite plasma S. S. Harilal, Riju 1996; accepted for publication 20 December 1996 The emission features of laser ablated graphite plume diagnostic technique. Time resolved optical emission spectroscopy is employed to reveal the velocity

  8. Delayed Development of Pneumothorax After Pulmonary Radiofrequency Ablation

    SciTech Connect (OSTI)

    Clasen, Stephan, E-mail: stephan.clasen@med.uni-tuebingen.d [Eberhard-Karls-University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Kettenbach, Joachim [Medical University of Vienna, Cardiovascular and Interventional Radiology, Department of Radiology (Austria); Kosan, Bora; Aebert, Hermann [Eberhard-Karls-University of Tuebingen, Department of Thoracic, Cardiac and Vascular Surgery (Germany); Schernthaner, Melanie [Medical University of Vienna, Cardiovascular and Interventional Radiology, Department of Radiology (Austria); Kroeber, Stefan-Martin [Eberhard-Karls-University of Tuebingen, Institute of Pathology (Germany); Boemches, Andrea [Eberhard-Karls-University of Tuebingen, Department of Thoracic, Cardiac and Vascular Surgery (Germany); Claussen, Claus D.; Pereira, Philippe L. [Eberhard-Karls-University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany)

    2009-05-15T23:59:59.000Z

    Acute pneumothorax is a frequent complication after percutaneous pulmonary radiofrequency (RF) ablation. In this study we present three cases showing delayed development of pneumothorax after pulmonary RF ablation in 34 patients. Our purpose is to draw attention to this delayed complication and to propose a possible approach to avoid this major complication. These three cases occurred subsequent to 44 CT-guided pulmonary RF ablation procedures (6.8%) using either internally cooled or multitined expandable RF electrodes. In two patients, the pneumothorax, being initially absent at the end of the intervention, developed without symptoms. One of these patients required chest drain placement 32 h after RF ablation, and in the second patient therapy remained conservative. In the third patient, a slight pneumothorax at the end of the intervention gradually increased and led into tension pneumothorax 5 days after ablation procedure. Underlying bronchopleural fistula along the coagulated former electrode track was diagnosed in two patients. In conclusion, delayed development of pneumothorax after pulmonary RF ablation can occur and is probably due to underlying bronchopleural fistula, potentially leading to tension pneumothorax. Patients and interventionalists should be prepared for delayed onset of this complication, and extensive track ablation following pulmonary RF ablation should be avoided.

  9. Atomistic simulation study of short pulse laser interactions with a metal target under conditions of spatial confinement by a transparent overlayer

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Atomistic simulation study of short pulse laser interactions with a metal target under conditions; accepted 7 April 2014; published online 8 May 2014) The distinct characteristics of short pulse laser. INTRODUCTION While the general mechanisms of short pulse laser melt- ing, spallation, and ablation of metals

  10. Femtosecond laser-drilled capillary integrated into a microfluidic device Tyson N. Kim, Kyle Campbell, Alex Groisman, David Kleinfeld, and Chris B. Schaffera

    E-Print Network [OSTI]

    Kleinfeld, David

    Femtosecond laser-drilled capillary integrated into a microfluidic device Tyson N. Kim, Kyle micromachining to add unmoldable features to the microfluidic devices. We apply laser ablation to drill channels. Finally, we use a laser-drilled microcapillary to trap a polystyrene bead by suction and hold

  11. Channels of energy redistribution in short-pulse laser interactions with metal targets

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Channels of energy redistribution in short-pulse laser interactions with metal targets Leonid V The kinetics and channels of laser energy redistribution in a target irradiated by a short, 1 ps, laser pulse of a target irradiated by a short laser pulse as well as on the characteristics of laser-induced phase

  12. Radiofrequency Ablation of Intrahepatic Cholangiocarcinoma: Preliminary Experience

    SciTech Connect (OSTI)

    Carrafiello, Gianpaolo, E-mail: gcarraf@tin.it; Lagana, Domenico; Cotta, Elisa; Mangini, Monica; Fontana, Federico; Bandiera, Francesca; Fugazzola, Carlo [University of Insubria c/o Ospedale di Circolo, Department of Radiology (Italy)

    2010-08-15T23:59:59.000Z

    The purpose of this study was to evaluate the safety and efficacy of percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) in patients with intrahepatic cholangiocarcinoma (ICCA) in a small, nonrandomized series. From February 2004 to July 2008, six patients (four men and two women; mean age 69.8 years [range 48 to 83]) with ICCA underwent percutaneous US-guided RFA. Preintervetional transarterial embolization was performed in two cases to decrease heat dispersion during RFA in order to increase the area of ablation. The efficacy of RFA was evaluated using contrast-enhanced dynamic computed tomography (CT) 1 month after treatment and then every 3 months thereafter. Nine RFA sessions were performed for six solid hepatic tumors in six patients. The duration of follow-up ranged from 13 to 21 months (mean 17.5). Posttreatment CT showed total necrosis in four of six tumors after one or two RFA sessions. Residual tumor was observed in two patients with larger tumors (5 and 5.8 cm in diameter). All patients tolerated the procedure, and there with no major complications. Only 1 patient developed post-RFA syndrome (pain, fever, malaise, and leukocytosis), which resolved with oral administration of acetaminophen. Percutaneous RFA is a safe and effective treatment for patients with hepatic tumors: It is ideally suited for those who are not eligible for surgery. Long-term follow-up data regarding local and systemic recurrence and survival are still needed.

  13. An International Pellet Ablation Database L.R. Baylor, A. Geraud*, W.A. Houlberg,

    E-Print Network [OSTI]

    An International Pellet Ablation Database L.R. Baylor, A. Geraud*, W.A. Houlberg, D. Frigione+, M of an international pellet ablation database (IPADBASE) that has been assembled to enable studies of pellet ablation theories that are used to describe the physics of an ablating fuel pellet in a tokamak plasma. The database

  14. Parameter Optimization for Laser Polishing of Niobium for SRF Applications

    SciTech Connect (OSTI)

    Zhao, Liang [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States) and William and Mary College, Williamsburg, VA (United States); Klopf, John Michael [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kelley, Michael J. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States) and William and Mary College, Williamsburg, VA (United States)

    2013-06-01T23:59:59.000Z

    Surface smoothness is critical to the performance of SRF cavities. As laser technology has been widely applied to metal machining and surface treatment, we are encouraged to use it on niobium as an alternative to the traditional wet polishing process where aggressive chemicals are involved. In this study, we describe progress toward smoothing by optimizing laser parameters on BCP treated niobium surfaces. Results shows that microsmoothing of the surface without ablation is achievable.

  15. Microwave Ablation of Porcine Kidneys in vivo: Effect of two Different Ablation Modes ('Temperature Control' and 'Power Control') on Procedural Outcome

    SciTech Connect (OSTI)

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Arnegger, F. [University Hospital Heidelberg, Department of General, Abdominal and Transplantation Surgery (Germany); Koch, V.; Pap, B.; Holzschuh, M.; Bellemann, N. [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Gehrig, T.; Senft, J.; Nickel, F. [University Hospital Heidelberg, Department of General, Abdominal and Transplantation Surgery (Germany); Mogler, C. [University Hospital Heidelberg, Department of General Pathology (Germany); Zelzer, S.; Meinzer, H. P. [German Cancer Research Center, Division of Medical and Biological Informatics (Germany); Stampfl, U.; Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

    2012-06-15T23:59:59.000Z

    Purpose: This study was designed to analyze the effect of two different ablation modes ('temperature control' and 'power control') of a microwave system on procedural outcome in porcine kidneys in vivo. Methods: A commercially available microwave system (Avecure Microwave Generator; MedWaves, San Diego, CA) was used. The system offers the possibility to ablate with two different ablation modes: temperature control and power control. Thirty-two microwave ablations were performed in 16 kidneys of 8 pigs. In each animal, one kidney was ablated twice by applying temperature control (ablation duration set point at 60 s, ablation temperature set point at 96 Degree-Sign C, automatic power set point; group I). The other kidney was ablated twice by applying power control (ablation duration set point at 60 s, ablation temperature set point at 96 Degree-Sign C, ablation power set point at 24 W; group II). Procedural outcome was analyzed: (1) technical success (e.g., system failures, duration of the ablation cycle), and (2) ablation geometry (e.g., long axis diameter, short axis diameter, and circularity). Results: System failures occurred in 0% in group I and 13% in group II. Duration of the ablation cycle was 60 {+-} 0 s in group I and 102 {+-} 21 s in group II. Long axis diameter was 20.3 {+-} 4.6 mm in group I and 19.8 {+-} 3.5 mm in group II (not significant (NS)). Short axis diameter was 10.3 {+-} 2 mm in group I and 10.5 {+-} 2.4 mm in group II (NS). Circularity was 0.5 {+-} 0.1 in group I and 0.5 {+-} 0.1 in group II (NS). Conclusions: Microwave ablations performed with temperature control showed fewer system failures and were finished faster. Both ablation modes demonstrated no significant differences with respect to ablation geometry.

  16. A Complicated Postsurgical Echinococcal Cyst Treated with Radiofrequency Ablation

    SciTech Connect (OSTI)

    Thanos, L., E-mail: Loutharad@yahoo.com; Mylona, S. [Korgialeneio-Benakeio 'Red Cross Hospital of Athens', Department of Radiology (Greece); Brontzakis, P. [Korgialeneio-Benakeio 'Red Cross Hospital of Athens', Department of Surgery (Greece); Ptohis, N. [Korgialeneio-Benakeio 'Red Cross Hospital of Athens', Department of Radiology (Greece); Karaliotas, K. [Korgialeneio-Benakeio 'Red Cross Hospital of Athens', Department of Surgery (Greece)

    2008-01-15T23:59:59.000Z

    Surgery of hydatid cysts is often complicated with intrabiliary rupture (IBR), which if not recognized may lead to biliary fistula with rather high rates of morbidity and mortality. We report our experience with the application of radiofrequency (RF) ablation for the treatment of an operated hepatic echinococcal cyst which was complicated with biliocystic communication and cysteocutaneous fistula with bile leakage. RF ablation was performed under CT guidance into the remaining cyst through the cutaneous fistula. Since ablation of the cyst and the fistula the patient has been asymptomatic.

  17. Effects of laser energy fluence on the onset and growth of the Rayleigh-Taylor instabilities and its influence on the topography of the Fe thin film grown in pulsed laser deposition facility

    SciTech Connect (OSTI)

    Mahmood, S. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Department of Physics, University of Karachi, Karachi 75270 (Pakistan); Rawat, R. S.; Wang, Y.; Lee, S.; Tan, T. L.; Springham, S. V.; Lee, P. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Zakaullah, M. [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

    2012-10-15T23:59:59.000Z

    The effect of laser energy fluence on the onset and growth of Rayleigh-Taylor (RT) instabilities in laser induced Fe plasma is investigated using time-resolved fast gated imaging. The snow plow and shock wave models are fitted to the experimental results and used to estimate the ablation parameters and the density of gas atoms that interact with the ablated species. It is observed that RT instability develops during the interface deceleration stage and grows for a considerable time for higher laser energy fluence. The effects of RT instabilities formation on the surface topography of the Fe thin films grown in pulsed laser deposition system are investigated (i) using different laser energy fluences for the same wavelength of laser radiation and (ii) using different laser wavelengths keeping the energy fluence fixed. It is concluded that the deposition achieved under turbulent condition leads to less smooth deposition surfaces with bigger sized particle agglomerates or network.

  18. Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650 nm to 4 µm were characterized by spatially resolved

  19. Infrared absorption spectroscopy and chemical kinetics of free radicals

    SciTech Connect (OSTI)

    Curl, R.F.; Glass, G.P. [Rice Univ., Houston, TX (United States)

    1993-12-01T23:59:59.000Z

    This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

  20. atrioventricular node ablation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    is performed in selected patients with a symptomatic premature ventricular complex (PVC) or PVC-induced cardiomyopathy. Ablation of PVC from the His region has a high risk of...

  1. Ultrashort pulse high repetition rate laser system for biological tissue processing

    DOE Patents [OSTI]

    Neev, J.; Da Silva, L.B.; Matthews, D.L.; Glinsky, M.E.; Stuart, B.C.; Perry, M.D.; Feit, M.D.; Rubenchik, A.M.

    1998-02-24T23:59:59.000Z

    A method and apparatus are disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment. 8 figs.

  2. Ultrashort pulse high repetition rate laser system for biological tissue processing

    DOE Patents [OSTI]

    Neev, Joseph (Laguna Beach, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis L. (Moss Beach, CA); Glinsky, Michael E. (Livermore, CA); Stuart, Brent C. (Fremont, CA); Perry, Michael D. (Livermore, CA); Feit, Michael D. (Livermore, CA); Rubenchik, Alexander M. (Livermore, CA)

    1998-01-01T23:59:59.000Z

    A method and apparatus is disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment.

  3. Spectroscopy, Kinetics, and Dynamics of Combustion Radicals

    SciTech Connect (OSTI)

    Nesbitt, David J. [Research/Professor

    2013-08-06T23:59:59.000Z

    Spectroscopy, kinetics and dynamics of jet cooled hydrocarbon transients relevant to the DOE combustion mission have been explored, exploiting i) high resolution IR lasers, ii) slit discharge sources for formation of jet cooled radicals, and iii) high sensitivity detection with direct laser absorption methods and near the quantum shot noise limit. What makes this combination powerful is that such transients can be made under high concentrations and pressures characteristic of actual combustion conditions, and yet with the resulting species rapidly cooled (T ?10-15K) in the slit supersonic expansion. Combined with the power of IR laser absorption methods, this provides novel access to spectral detection and study of many critical combustion species.

  4. Statistical Algorithms for Simulation of Electron Quantum Kinetics in Semiconductors -Part II

    E-Print Network [OSTI]

    Whitlock, Paula

    Statistical Algorithms for Simulation of Electron Quantum Kinetics in Semiconductors - Part II M describes the relaxation of semiconductor elec- trons initially excited by a laser pulse [1]. The equation

  5. LLE (Laboratory for Laser Energetics) review

    SciTech Connect (OSTI)

    Kumpan, S.A. (ed.)

    1990-01-01T23:59:59.000Z

    This volume of the LLE Review, covering the period April--June 1990, contains articles in two main sections, Progress in Laser Fusion and Advanced Technology Developments. The first article presents the theoretical interpretation of the glass-ablator cryogenic-implosion experiments recently conducted on OMEGA. It is followed by an article describing the analysis of neutron time-of-flight data taken during DT and DD experiments; and a discussion of the improvements to laser diagnostics that now provide for precise control of the OMEGA laser is given. This paper contains a report on the development of transparent conductive coatings for KDP crystals, and a discussion of the study of the transient-surface Debye-Waller effect in materials irradiated with an ultrafast laser.

  6. Picoseconds-Laser Modification of Thin Films

    SciTech Connect (OSTI)

    Gakovic, Biljana; Trtica, Milan [Institute of Nuclear Sciences 'VINCA' 522, 11001 Belgrade (Serbia and Montenegro); Batani, Dimitri; Desai, Tara; Redaelli, Renato [Dipartimento di Fisica 'G. Occhialini', Universita' degli Studi Milano-Bicocca, Piazza della Scienza 3, Milan 20126 (Italy)

    2006-04-07T23:59:59.000Z

    The interaction of a Nd:YAG laser, pulse duration of 40 ps, with a titanium nitride (TiN) and tungsten-titanium (W-Ti) thin films deposited at silicon was studied. The peak intensity on targets was up to 1012 W/cm2. Results have shown that the TiN surface was modified, by the laser beam, with energy density of {>=}0.18 J/cm2 ({lambda}laser= 532 nm) as well as of 30.0 J/cm2 ({lambda}laser= 1064 nm). The W-Ti was surface modified with energy density of 5.0 J/cm2 ({lambda}laser= 532 nm). The energy absorbed from the Nd:YAG laser beam is partially converted to thermal energy, which generates a series of effects such as melting, vaporization of molten materials, dissociation and ionization of the vaporized material, appearance of plasma, etc. The following morphological changes of both targets were observed: (i) The appearance of periodic microstructures, in the central zone of the irradiated area, for laser irradiation at 532 nm. Accumulation of great number of laser pulses caused film ablation and silicon modification. (ii) Hole formation on the titanium nitride/silicon target was registered at 1064 nm. The process of the Nd:YAG laser interaction with both targets was accompanied by plasma formation above the target.

  7. Development of pulse laser processing for mounting fiber Bragg grating

    SciTech Connect (OSTI)

    Nishimura, Aikihko; Shimada, Yukihiro; Yonemoto, Yukihiro; Suzuki, Hirokazu; Ishibashi, Hisayoshi [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umebidai Kidugawa Kyoto 619-0215 (Japan); Applied Laser Technology Institute, Tsuruga Head Office, Japan Atomic Energy Agency, 65-20 Kizaki Tsuruga Fukui 914-8585 (Japan); Technical Research and Development Institute, Kumagai Gumi Co., Ltd., 2-1 Tsukudo, Shinjuku Tokyo 162-8557 (Japan)

    2012-07-11T23:59:59.000Z

    Pulse laser processing has been developed for the application of industrial plants in monitoring and maintenance. Surface cleaning by nano-second laser ablation was demonstrated for decontamination of oxide layers of Cr contained steel. Direct writing by femtosecond processing induced a Bragg grating in optical fiber to make it a seismic sensor for structural health monitoring. Adhesive cement was used to fix the seismic sensor on the surface of reactor coolant pipe material. Pulse laser processing and its related technologies were presented to overcome the severe accidents of nuclear power plants.

  8. Composition analysis by scanning femtosecond laser ultraprobing (CASFLU).

    DOE Patents [OSTI]

    Ishikawa, Muriel Y. (Livermore, CA); Wood, Lowell L. (Simi Valley, CA); Campbell, E. Michael (Danveille, CA); Stuart, Brent C. (Livermore, CA); Perry, Michael D. (Livermore, CA)

    2002-01-01T23:59:59.000Z

    The composition analysis by scanning femtosecond ultraprobing (CASFLU) technology scans a focused train of extremely short-duration, very intense laser pulses across a sample. The partially-ionized plasma ablated by each pulse is spectrometrically analyzed in real time, determining the ablated material's composition. The steering of the scanned beam thus is computer directed to either continue ablative material-removal at the same site or to successively remove nearby material for the same type of composition analysis. This invention has utility in high-speed chemical-elemental, molecular-fragment and isotopic analyses of the microstructure composition of complex objects, e.g., the oxygen isotopic compositions of large populations of single osteons in bone.

  9. Incidence and Cause of Hypertension During Adrenal Radiofrequency Ablation

    SciTech Connect (OSTI)

    Yamakado, Koichiro, E-mail: yama@clin.medic.mie-u.ac.jp; Takaki, Haruyuki [Mie University School of Medicine, Department of Interventional Radiology (Japan); Yamada, Tomomi [Mie University School of Medicine, Department of Translational Medicine (Japan); Yamanaka, Takashi; Uraki, Junji; Kashima, Masataka; Nakatsuka, Atsuhiro; Takeda, Kan [Mie University School of Medicine, Department of Interventional Radiology (Japan)

    2012-12-15T23:59:59.000Z

    Purpose: To evaluate the incidence and cause of hypertension prospectively during adrenal radiofrequency ablation (RFA). Methods: For this study, approved by our institutional review board, written informed consent was obtained from all patients. Patients who received RFA for adrenal tumors (adrenal ablation) and other abdominal tumors (nonadrenal ablation) were included in this prospective study. Blood pressure was monitored during RFA. Serum adrenal hormone levels including epinephrine, norepinephrine, dopamine, and cortisol levels were measured before and during RFA. The respective incidences of procedural hypertension (systolic blood pressure >200 mmHg) of the two patient groups were compared. Factors correlating with procedural systolic blood pressure were evaluated by regression analysis.ResultsNine patients underwent adrenal RFA and another 9 patients liver (n = 5) and renal (n = 4) RFA. Asymptomatic procedural hypertension that returned to the baseline by injecting calcium blocker was found in 7 (38.9%) of 18 patients. The incidence of procedural hypertension was significantly higher in the adrenal ablation group (66.7%, 6/9) than in the nonadrenal ablation group (11.1%, 1/9, P < 0.0498). Procedural systolic blood pressure was significantly correlated with serum epinephrine (R{sup 2} = 0.68, P < 0.0001) and norepinephrine (R{sup 2} = 0.72, P < 0.0001) levels during RFA. The other adrenal hormones did not show correlation with procedural systolic blood pressure. Conclusion: Hypertension occurs frequently during adrenal RFA because of the release of catecholamine.

  10. Generation and use of high power 213 nm and 266 nm laser radiation and tunable 210-400 nm laser radiation with BBO crystal matrix array

    DOE Patents [OSTI]

    Gruen, Dieter M. (Downers Grove, IL)

    2000-01-01T23:59:59.000Z

    A 213 nm laser beam is capable of single photon ablative photodecomposition for the removal of a polymer or biological material substrate. Breaking the molecular bonds and displacing the molecules away from the substrate in a very short time period results in most of the laser photon energy being carried away by the displaced molecules, thus minimizing thermal damage to the substrate. The incident laser beam may be unfocussed and is preferably produced by quintupling the 1064 nm radiation from a Nd:YAG solid state laser, i.e., at 213 nm. In one application, the 213 nm laser beam is expanded in cross section and directed through a plurality of small beta barium borate (BBO) crystals for increasing the energy per photon of the laser radiation directed onto the substrate. The BBO crystals are arranged in a crystal matrix array to provide a large laser beam transmission area capable of accommodating high energy laser radiation without damaging the BBO crystals. The BBO crystal matrix array may also be used with 266 nm laser radiation for carrying out single or multi photon ablative photodecomposition. The BBO crystal matrix array may also be used in an optical parametric oscillator mode to generate high power tunable laser radiation in the range of 210-400 nm.

  11. Laser induced plasma on copper target, a non-equilibrium model

    SciTech Connect (OSTI)

    Oumeziane, Amina Ait, E-mail: a.aitoumeziane@gmail.com; Liani, Bachir [Laboratoire de Physique Théorique, Abou Beker Blekaid University, Tlemcen (Algeria)] [Laboratoire de Physique Théorique, Abou Beker Blekaid University, Tlemcen (Algeria); Parisse, Jean-Denis [IUSTI UMR CNRS 7343, Aix-Marseille University, Marseille (France)] [IUSTI UMR CNRS 7343, Aix-Marseille University, Marseille (France)

    2014-02-15T23:59:59.000Z

    The aim of this work is to present a comprehensive numerical model for the UV laser ablation of metal targets, it focuses mainly on the prediction of laser induced plasma thresholds, the effect of the laser-plasma interaction, and the importance of the electronic non-equilibrium in the laser induced plume and its expansion in the background gas. This paper describes a set of numerical models for laser-matter interaction between 193-248 and 355?nm lasers and a copper target. Along with the thermal effects inside the material resulting from the irradiation of the latter with the pulsed laser, the laser-evaporated matter interaction and the plasma formation are thoroughly modelled. In the laser induced plume, the electronic nonequilibrium and the laser beam absorption have been investigated. Our calculations of the plasmas ignition thresholds on copper targets have been validated and compared to experimental as well as theoretical results. Comparison with experiment data indicates that our results are in good agreement with those reported in the literature. Furthermore, the inclusion of electronic non-equilibrium in our work indicated that this important process must be included in models of laser ablation and plasma plume formation.

  12. ACTION DE L'ABLATION DES BULBES OLFACTIFS SUR LES MCANISMES DE LA REPRODUCTION

    E-Print Network [OSTI]

    Boyer, Edmond

    ACTION DE L'ABLATION DES BULBES OLFACTIFS SUR LES MÉCANISMES DE LA REPRODUCTION CHEZ LA TRUIE J. P Recheyches zoolechniques, Jouy-en-Josas (Seine et Oise). SOMMAIRE L'ablation chirurgicale des bulbes involution utérine. L'ablation totale des bulbes olfactifs semble donc perturber la décharge des hormones

  13. Thermal Protection with 5% Dextrose Solution Blanket During Radiofrequency Ablation

    SciTech Connect (OSTI)

    Chen, Enn Alexandria, E-mail: echen@cc.nih.gov; Neeman, Ziv; Lee, Fred T.; Kam, Anthony; Wood, Brad [National Institutes of Health, Radiology Department, Warren G. Magmison Clinical Center (United States)

    2006-12-15T23:59:59.000Z

    A serious complication for any thermal radiofrequency ablation is thermal injury to adjacent structures, particularly the bowel, which can result in additional major surgery or death. Several methods using air, gas, fluid, or thermometry to protect adjacent structures from thermal injury have been reported. In the cases presented in this report, 5% dextrose water (D5W) was instilled to prevent injury to the bowel and diaphragm during radiofrequency ablation. Creating an Insulating envelope or moving organs with D5W might reduce risk for complications such as bowel perforation.

  14. LLE Quarterly Report (July-September 1999)[Library for Laser Energetics

    SciTech Connect (OSTI)

    NONE

    2000-01-07T23:59:59.000Z

    This volume of the LLE Review, covering the period July-September 1999, features a theoretical analysis of a process that generates mass perturbations of an imploding target driven by modulated laser illumination. The process, referred to as laser imprint, impacts the integrity of the shell during direct-drive implosions, potentially quenching target performance. In this article V. N. Goncharov, J. A. Delettrez, S. Skupsky, and R. P. J. Town present a model of the generation of mass perturbations and analyze the mass perturbation growth due to nonuniform ablation pressure. Stabilizing mechanisms of thermal conduction smoothing and mass ablation are shown to suppress the acceleration perturbation, and mass ablation is also shown to impact velocity perturbations. The model predicts that a direct-drive cryogenic NIF target will remain intact during the implosion when l-Thz SSD beam smoothing is used.

  15. Plasmadynamics and ionization kinetics of thermionic energy conversion

    SciTech Connect (OSTI)

    Lawless, J.L. Jr.

    1981-01-01T23:59:59.000Z

    To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type Cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional Cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. The effects of the complete system of electron-atom inelastic collisions on the ionization-recombination problem are shown to reduce to a system nearly as simple as the well-known one-quantum approximation. To combine the above analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. Using the above developments, a proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a Cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed.

  16. High Energy Laser for Space Debris Removal

    SciTech Connect (OSTI)

    Barty, C; Caird, J; Erlandson, A; Beach, R; Rubenchik, A

    2009-10-30T23:59:59.000Z

    The National Ignition Facility (NIF) and Photon Science Directorate at Lawrence Livermore National Laboratory (LLNL) has substantial relevant experience in the construction of high energy lasers, and more recently in the development of advanced high average power solid state lasers. We are currently developing new concepts for advanced solid state laser drivers for the Laser Inertial Fusion Energy (LIFE) application, and other high average power laser applications that could become central technologies for use in space debris removal. The debris population most readily addressed by our laser technology is that of 0.1-10 cm sized debris in low earth orbit (LEO). In this application, a ground based laser system would engage an orbiting target and slow it down by ablating material from its surface which leads to reentry into the atmosphere, as proposed by NASA's ORION Project. The ORION concept of operations (CONOPS) is also described in general terms by Phipps. Key aspects of this approach include the need for high irradiance on target, 10{sup 8} to 10{sup 9} W/cm{sup 2}, which favors short (i.e., picoseconds to nanoseconds) laser pulse durations and high energy per pulse ({approx} > 10 kJ). Due to the target's orbital velocity, the potential duration of engagement is only of order 100 seconds, so a high pulse repetition rate is also essential. The laser technology needed for this application did not exist when ORION was first proposed, but today, a unique combination of emerging technologies could create a path to enable deployment in the near future. Our concepts for the laser system architecture are an extension of what was developed for the National Ignition Facility (NIF), combined with high repetition rate laser technology developed for Inertial Fusion Energy (IFE), and heat capacity laser technology developed for military applications. The 'front-end' seed pulse generator would be fiber-optics based, and would generate a temporally, and spectrally tailored pulse designed for high transmission through the atmosphere, as well as efficient ablative coupling to the target. The main amplifier would use either diode-pumped or flashlamp-pumped solid state gain media, depending on budget constraints of the project. A continuously operating system would use the gas-cooled amplifier technology developed for Mercury, while a burst-mode option would use the heat capacity laser technology. The ground-based system that we propose is capable of rapid engagement of targets whose orbits cross over the site, with potential for kill on a single pass. Very little target mass is ablated per pulse so the potential to create additional hazardous orbiting debris is minimal. Our cost estimates range from $2500 to $5000 per J depending on choices for laser gain medium, amplifier pump source, and thermal management method. A flashlamp-pumped, Nd:glass heat-capacity laser operating in the burst mode would have costs at the lower end of this spectrum and would suffice to demonstrate the efficacy of this approach as a prototype system. A diode-pumped, gas-cooled laser would have higher costs but could be operated continuously, and might be desirable for more demanding mission needs. Maneuverability can be incorporated in the system design if the additional cost is deemed acceptable. The laser system would need to be coupled with a target pointing and tracking telescope with guide-star-like wavefront correction capability.

  17. Nanosecond-laser plasma-assisted ultradeep microdrilling of optically opaque and transparent solids

    SciTech Connect (OSTI)

    Paul, Stanley; Kudryashov, Sergey I.; Lyon, Kevin; Allen, Susan D. [Department of Chemistry and Physics, Arkansas State University, State University, Arkansas 72467-0419 (United States)

    2007-02-15T23:59:59.000Z

    A mechanism of ultradeep (up to tens of microns per pulse, submillimeter total hole depths) plasma-assisted ablative drilling of optically opaque and transparent materials by high-power nanosecond lasers has been proposed and verified experimentally using optical transmission and contact photoacoustic techniques to measure average drilling rates per laser shot versus laser intensity at constant focusing conditions. The plots of average drilling rates versus laser intensity exhibit slopes which are in good agreement with those predicted by the proposed model and also with other experimental studies. The proposed ultradeep drilling mechanism consists of a number of stages, including ultradeep 'nonthermal' energy delivery into bulk solids by the short-wavelength radiation of the hot ablative plasma, bulk heating and melting, accompanied by subsurface boiling in the melt pool, and resulting melt expulsion from the target.

  18. Radiofrequency Ablation of Subpleural Lung Malignancy: Reduced Pain Using an Artificially Created Pneumothorax

    SciTech Connect (OSTI)

    Lee, Edward W., E-mail: EdwardLee@mednet.ucla.edu; Suh, Robert D., E-mail: rsuh@mednet.ucla.ed [David Geffen School of Medicine at UCLA, Department of Radiological Sciences, Thoracic Imaging and Intervention, Center for the Health Sciences (CHS), UCLA Medical Center (United States); Zeidler, Michelle R. [David Geffen School of Medicine at UCLA, Department of Internal Medicine, Pulmonary and Critical Care (United States); Tsai, Irene S. [David Geffen School of Medicine at UCLA, Department of Radiological Sciences, Thoracic Imaging and Intervention, Center for the Health Sciences (CHS), UCLA Medical Center (United States); Cameron, Robert B. [David Geffen School of Medicine at UCLA, Department of Surgery, Thoracic Oncology (United States); Abtin, Fereidoun G.; Goldin, Jonathan G. [David Geffen School of Medicine at UCLA, Department of Radiological Sciences, Thoracic Imaging and Intervention, Center for the Health Sciences (CHS), UCLA Medical Center (United States)

    2009-07-15T23:59:59.000Z

    One of the main issues with radiofrequency (RF) ablation of the subpleural lung malignancy is pain management during and after RF ablation. In this article, we present a case that utilized a technique to decrease the pain associated with RF ablation of a malignancy located within the subpleural lung. Under CT guidance, we created an artificial pneumothorax prior to the RF ablation, which resulted in minimizing the pain usually experienced during and after the procedure. It also decreased the amount of pain medications usually used in patients undergoing RF ablation of a subpleural lung lesion.

  19. Structure of an Exploding Laser-Produced Plasma A. Collette* and W. Gekelman

    E-Print Network [OSTI]

    California at Los Angles, University of

    the background field (a diamagnetic cavity or ``mag- netic bubble''), and large ( Án n $ 1) field-aligned density rep rate. The expanding plasma is formed by laser ablation of a solid cylindrical carbon target to the 1 Hz repetition rate of the LaPD background plasma isfocusedtoan0.5 mm spot onthe carbon cylinder

  20. Varadhan and Mueller / Ablation Volume Rendering 1. Introduction

    E-Print Network [OSTI]

    Mueller, Klaus

    energy the material requires to change its state as well as its ability to absorb the incoming energy not just one phase change, as had been predicted previously, but two [3]. The ways in which heat propagates tissue. In the process of ablation, as heat energy impinges onto the material, the material responds

  1. Irreversible Electroporation for Focal Ablation at the Porta Hepatis

    SciTech Connect (OSTI)

    Kasivisvanathan, Veeru, E-mail: vk103@ic.ac.uk [Imperial College London, Department of Radiology (United Kingdom); Thapar, Ankur, E-mail: a.thapar09@imperial.ac.uk; Oskrochi, Youssof, E-mail: Youssof.Oskrochi09@imperial.ac.uk [Imperial College London, Department of Surgery and Cancer (United Kingdom); Picard, John, E-mail: John.picard@imperial.nhs.uk [Imperial College Healthcare NHS Trust, Department of Anaesthesia (United Kingdom); Leen, Edward L. S., E-mail: Edward.leen@imperial.ac.uk [Imperial College London, Department of Radiology (United Kingdom)

    2012-12-15T23:59:59.000Z

    Patients with chemotherapy-refractory liver metastases who are not candidates for surgery may be treated with focal ablation techniques with established survival benefits. Irreversible electroporation is the newest of these and has the putative advantages of a nonthermal action, preventing damage to adjacent biliary structures and bowel. This report describes the use of irreversible electroporation in a 61-year-old man with a solitary chemoresistant liver metastasis unsuitable for radiofrequency ablation as a result of its proximity to the porta hepatis. At 3 months, tumor size was decreased on computed tomography from 28 Multiplication-Sign 19 to 20 Multiplication-Sign 17 mm, representing stable disease according to the response evaluation criteria in solid tumors. This corresponded to a decrease in tumor volume size from 5.25 to 3.16 cm{sup 3}. There were no early or late complications. Chemoresistant liver metastases in the proximity of the porta hepatis that are considered to be too high a risk for conventional surgery or thermal ablation may be considered for treatment by the novel ablation technique of irreversible electroporation.

  2. Palliation of Painful Perineal Metastasis Treated with Radiofrequency Thermal Ablation

    SciTech Connect (OSTI)

    Thanos, L., E-mail: loutharad@yahoo.com; Mylona, S.; Kalioras, V.; Pomoni, M.; Batakis, N. [Red-Cross Hospital of Athens, Radiology Department, 'Korgialeneio-Benakeio' (Greece)

    2005-04-15T23:59:59.000Z

    We report a case of painful perineal metastasis from urinary bladder carcinoma in a 73-years-old woman, treated with CT-guided radiofrequency ablation (RFA). The pain was immediately relieved and follow-up at 1 and 6 months showed total necrosis of the mass. One year later, the patient has no pain and her quality of life is improved.

  3. ablative materials: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ablative materials First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Photochemical induced effects in...

  4. Measurements of Cavitation Dose, Echogenicity, and Temperature during Ultrasound Ablation

    E-Print Network [OSTI]

    Mast, T. Douglas

    Measurements of Cavitation Dose, Echogenicity, and Temperature during Ultrasound Ablation T traces from the array, time-domain signals received by a 1 MHz, unfocused passive cavitation detector signals received by the array. Cavitation dose was quantified from the spectra of signals measured

  5. A model for self-defocusing in laser drilling of polymeric materials

    SciTech Connect (OSTI)

    Zhang Chong; Quick, Nathaniel R.; Kar, Aravinda [Department of Mechanical, Materials and Aerospace Engineering, College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States); AppliCote Associates, LLC, 1445 Dolgner Place, Suite 23, Sanford, Florida 32771 (United States); College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States)

    2008-01-01T23:59:59.000Z

    A numerical thermal model is presented for laser microvias drilling in multilayer electronic substrates with Nd:YAG (YAG denotes yttrium aluminum garnet) and CO{sub 2} lasers. Such substrates have different optical properties such as the refractive index and absorption coefficient at these two laser wavelengths, resulting in different drilling mechanisms. Since the skin depth of the polymer is large for both the lasers, volumetric heating is considered in the model. As soon as a small cavity is formed during the drilling process, the concave curvature of the drilling front acts as a concave lens that diverges the incident laser beam. This self-defocusing effect can greatly reduce the drilling speed as predicted by the model. This effect makes the refractive index of the substrate at different wavelengths an important parameter for laser drilling. The model was used to calculate the laser ablation thresholds which were found to be 8 and 56 J/cm{sup 2} for the CO{sub 2} and Nd:YAG lasers respectively. Due to the expulsion of materials because of high internal pressures in the case of Nd:YAG laser microvia drilling, the ablation threshold may be far below the calculated value. A particular laser beam shape, such as pitch fork, was found to drill better holes than the Gaussian beam.

  6. Excessive Hyperthermic Necrosis of a Pulmonary Lobe after Hypertonic Saline-Enhanced Monopolar Radiofrequency Ablation

    SciTech Connect (OSTI)

    Kim, Tae Sung, E-mail: tskim@smc.samsung.co.kr; Lim, Hyo K. [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center (Korea, Republic of); Kim, Hojoong [Sungkyunkwan University School of Medicine, Division of Pulmonary and Critical Care Medicine, The Department of Medicine, Samsung Medical Center (Korea, Republic of)

    2006-02-15T23:59:59.000Z

    Although there has been a feasibility study of saline-enhanced radiofrequency ablation of the lung in rabbits, there has been no report on hypertonic saline-enhanced radiofrequency ablation of human pulmonary tumors or its complication. We report a case in which a large necrotic cavity was produced in the lung after hypertonic saline-enhanced radiofrequency ablation of recurrent metastatic tumor from hepatocellular carcinoma. Although hypertonic saline-enhanced radiofrequency ablation is powerful and efficient in local ablation, it is difficult to predict the exact extent of ablation, especially in the lungs. This can be dangerous, as there is a high chance of producing an ablation area much larger than expected and, hence, major complications. Special attention is required not to overablate while using this technique.

  7. Streaked x-ray microscopy of laser-fusion targets

    SciTech Connect (OSTI)

    Price, R.H.; Campbell, E.M.; Rosen, M.D.; Auerbach, J.M.; Phillion, D.W.; Whitlock, R.R.; Obenshain, S.P.; McLean, E.A.; Ripin, B.H.

    1982-08-01T23:59:59.000Z

    An ultrafast soft x-ray streak camera has been coupled to a Wolter axisymmetric x-ray microscope. This system was used to observe the dynamics of laser fusion targets both in self emission and backlit by laser produced x-ray sources. Spatial resolution was 7 ..mu..m and temporal resolution was 20 ps. Data is presented showing the ablative acceleration of foils to velocities near 10/sup 7/ cm/sec and the collision of an accelerated foil with a second foil, observed using 3 keV streaked x-ray backlighting. Good agreement was found between hydrocode simulations, simple models of the ablative acceleration and the observed velocities of the carbon foils.

  8. Lung Tumor Radiofrequency Ablation: Where Do We Stand?

    SciTech Connect (OSTI)

    Baere, Thierry de, E-mail: debaere@igr.fr [Institut Gustave Roussy, Department of Interventional Radiology (France)

    2011-04-15T23:59:59.000Z

    Today, radiofrequency ablation (RFA) of primary and metastatic lung tumor is increasingly used. Because RFA is most often used with curative intent, preablation workup must be a preoperative workup. General anesthesia provides higher feasibility than conscious sedation. The electrode positioning must be performed under computed tomography for sake of accuracy. The delivery of RFA must be adapted to tumor location, with different impedances used when treating tumors with or without pleural contact. The estimated rate of incomplete local treatment at 18 months was 7% (95% confidence interval, 3-14) per tumor, with incomplete treatment depicted at 4 months (n = 1), 6 months (n = 2), 9 months (n = 2), and 12 months (n = 2). Overall survival and lung disease-free survival at 18 months were, respectively, 71 and 34%. Size is a key point for tumor selection because large size is predictive of incomplete local treatment and poor survival. The ratio of ablation volume relative to tumor volume is predictive of complete ablation. Follow-up computed tomography that relies on the size of the ablation zone demonstrates the presence of incomplete ablation. Positron emission tomography might be an interesting option. Chest tube placement for pneumothorax is reported in 8 to 12%. Alveolar hemorrhage and postprocedure hemoptysis occurred in approximately 10% of procedures and rarely required specific treatment. Death was mostly related to single-lung patients and hilar tumors. No modification of forced expiratory volume in the first second between pre- and post-RFA at 2 months was found. RFA in the lung provides a high local efficacy rate. The use of RFA as a palliative tool in combination with chemotherapy remains to be explored.

  9. Ablation Plume Dynamics in a Background Gas

    SciTech Connect (OSTI)

    Amoruso, Salvatore [CNR-SPIN and Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Schou, Joergen [Deparment of Photonics Engineering, Risoe Campus, Technical University of Denmark, DK-4000 Roskilde (Denmark); Lunney, James G. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2010-10-08T23:59:59.000Z

    The expansion of a plume in a background gas of pressure comparable to that used in pulsed laser deposition (PLD) has been analyzed in terms of the model of Predtechensky and Mayorov (PM). This approach gives a relatively clear and simple description of the essential hydrodynamics during the expansion. The model also leads to an insightful treatment of the stopping behavior in dimensionless units for plumes and background gases of different atomic/molecular masses. The energetics of the plume dynamics can also be treated with this model. Experimental time-of-flight data of silver ions in a neon background gas show a fair agreement with predictions from the PM-model. Finally we discuss the validity of the model, if the work done by the pressure of the background gas is neglected.

  10. Erbium hydride decomposition kinetics.

    SciTech Connect (OSTI)

    Ferrizz, Robert Matthew

    2006-11-01T23:59:59.000Z

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  11. Kinetic theory viscosity

    E-Print Network [OSTI]

    C. J. Clarke; J. E. Pringle

    2004-03-17T23:59:59.000Z

    We show how the viscous evolution of Keplerian accretion discs can be understood in terms of simple kinetic theory. Although standard physics texts give a simple derivation of momentum transfer in a linear shear flow using kinetic theory, many authors, as detailed by Hayashi & Matsuda 2001, have had difficulties applying the same considerations to a circular shear flow. We show here how this may be done, and note that the essential ingredients are to take proper account of, first, isotropy locally in the frame of the fluid and, second, the geometry of the mean flow.

  12. Spectroscopy and kinetics of combustion gases at high temperatures

    SciTech Connect (OSTI)

    Hanson, R.K.; Bowman, C.T. [Stanford Univ., CA (United States)

    1993-12-01T23:59:59.000Z

    This program involves two complementary activities: (1) development and application of cw ring dye laser absorption methods for sensitive detection of radical species and measurement of fundamental spectroscopic parameters at high temperatures; and (2) shock tube studies of reaction kinetics relevant to combustion. Species currently under investigation in the spectroscopic portion of the research include NO and CH{sub 3}; this has necessitated the continued operated at wavelengths in the range 210-230 nm. Shock tube studies of reaction kinetics currently are focussed on reactions involving CH{sub 3} radicals.

  13. Fast neutron production from lithium converters and laser driven protons

    SciTech Connect (OSTI)

    Storm, M.; Jiang, S.; Wertepny, D.; Orban, C.; Morrison, J.; Willis, C.; McCary, E.; Balencourt, P.; Snyder, J.; Chowdhury, E.; Freeman, R. R.; Akli, K. [Department of Physics, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio 43210 (United States)] [Department of Physics, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio 43210 (United States); Bang, W.; Gaul, E.; Dyer, G.; Ditmire, T. [Department of Physics, Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas 78712 (United States)] [Department of Physics, Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas 78712 (United States)

    2013-05-15T23:59:59.000Z

    Experiments to generate neutrons from the {sup 7}Li(p,n){sup 7}Be reaction with 60 J, 180 fs laser pulses have been performed at the Texas Petawatt Laser Facility at the University of Texas at Austin. The protons were accelerated from the rear surface of a thin target membrane using the target-normal-sheath-acceleration mechanism. The neutrons were generated in nuclear reactions caused by the subsequent proton bombardment of a pure lithium foil of natural isotopic abundance. The neutron energy ranged up to 2.9 MeV. The total yield was estimated to be 1.6 × 10{sup 7} neutrons per steradian. An extreme ultra-violet light camera, used to image the target rear surface, correlated variations in the proton yield and peak energy to target rear surface ablation. Calculations using the hydrodynamics code FLASH indicated that the ablation resulted from a laser pre-pulse of prolonged intensity. The ablation severely limited the proton acceleration and neutron yield.

  14. Page 1Laser Safety Training Laser Institute of America Laser Safety Laser Institute of America

    E-Print Network [OSTI]

    Farritor, Shane

    Page 1Laser Safety Training © Laser Institute of America 1 Laser Safety © Laser Institute of America Laser Safety: Hazards, Bioeffects, and Control Measures Laser Institute of America Gus Anibarro Education Manager 2Laser Safety © Laser Institute of America Laser Safety Overview Laser Safety Accidents

  15. Laser Telecommunication timeLaser beam

    E-Print Network [OSTI]

    La Rosa, Andres H.

    Laser Telecommunication Experiment Laser time Laser beam intensity timeLaser beam Laser battery Laser connected to a circuit without a modulator. Bottom graph illustrates what happen when a modulating signal is superimposed to the DC voltage driving the laser Laser beam intensity DC Input voltage DC

  16. Dynamics of femtosecond laser produced tungsten nanoparticle plumes

    SciTech Connect (OSTI)

    Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); School of Physics and Optical Engineering, Dalian University of Technology, Dalian 116024 (China); Kozhevin, V. M. [Ioffe Physics Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)] [Ioffe Physics Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

    2013-11-28T23:59:59.000Z

    We investigated the expansion features of femtosecond laser generated tungsten nanoparticle plumes in vacuum. Fast gated images showed distinct two components expansion features, viz., plasma and nanoparticle plumes, separated by time of appearance. The persistence of plasma and nanoparticle plumes are ?500 ns and ?100 ?s, respectively, and propagating with velocities differed by 25 times. The estimated temperature of the nanoparticles showed a decreasing trend with increasing time and space. Compared to low-Z materials (e.g., Si), ultrafast laser ablation of high-Z materials like W provides significantly higher nanoparticle yield. A comparison between the nanoparticle plumes generated by W and Si is also discussed along with other metals.

  17. Commercialization plan laser-based decoating systems

    SciTech Connect (OSTI)

    Freiwald, J.; Freiwald, D.A.

    1998-01-01T23:59:59.000Z

    F2 Associates Inc. (F2) is a small, high-technology firm focused on developing and commercializing environmentally friendly laser ablation systems for industrial-rate removal of surface coatings from metals, concrete, and delicate substrates such as composites. F2 has a contract with the US Department of Energy Federal Energy Technology Center (FETC) to develop and test a laser-based technology for removing contaminated paint and other contaminants from concrete and metal surfaces. Task 4.1 in Phase 2 of the Statement of Work for this DOE contract requires that F2 ``document its plans for commercializing and marketing the stationary laser ablation system. This document shall include a discussion of prospects for commercial customers and partners and may require periodic update to reflect changing strategy. This document shall be submitted to the DOE for review.`` This report is being prepared and submitted in fulfillment of that requirement. This report describes the laser-based technology for cleaning and coatings removal, the types of laser-based systems that have been developed by F2 based on this technology, and the various markets that are emerging for this technology. F2`s commercialization and marketing plans are described, including how F2`s organization is structured to meet the needs of technology commercialization, F2`s strategy and marketing approach, and the necessary steps to receive certification for removing paint from aircraft and DOE certification for D and D applications. The future use of the equipment built for the DOE contract is also discussed.

  18. Bronchopleural Fistula After Radiofrequency Ablation of Lung Tumours

    SciTech Connect (OSTI)

    Cannella, Mathieu; Cornelis, Francois; Descat, Edouard; Ferron, Stephane; Carteret, Thibault; Castagnede, Hugues; Palussiere, Jean, E-mail: palussiere@bergonie.org [Regional Cancer Center, Department of Interventional Radiology, Institut Bergonie (France)

    2011-02-15T23:59:59.000Z

    The present article describes two cases of bronchopleural fistula (BPF) occurring after radiofrequency ablation of lung tumors. Both procedures were carried out using expandable multitined electrodes, with no coagulation of the needle track. After both ablations, ground-glass opacities encompassed the nodules and abutted the visceral pleura. The first patient had a delayed pneumothorax, and the second had a recurrent pneumothorax. Both cases of BPF were diagnosed on follow-up computed tomography chest scans (i.e., visibility of a distinct channel between the lung or a peripheral bronchus and the pleura) and were successfully treated with chest tubes alone. Our goal is to highlight the fact that BPF can occur without needle-track coagulation and to suggest that minimally invasive treatment is sufficient to cure BPFs of this specific origin.

  19. Laparoscopic Ultrasound-Guided Radiofrequency Ablation of Uterine Fibroids

    SciTech Connect (OSTI)

    Milic, Andrea [University of Toronto, Department of Medical Imaging (Canada); Asch, Murray R. [Lakeridge Health Corporation, Department of Diagnostic Radiology (Canada)], E-mail: masch@lakeridgehealth.on.ca; Hawrylyshyn, Peter A.; Allen, Lisa M. [Mount Sinai Hospital, Department of Obstetrics and Gynecology (Canada); Colgan, Terence J. [Mount Sinai Hospital, Department of Pathology (Canada); Kachura, John R. [Toronto General Hospital, Department of Diagnostic Imaging (Canada); Hayeems, Eran B. [Mount Sinai Hospital, Department of Diagnostic Imaging (Canada)

    2006-08-15T23:59:59.000Z

    Four patients with symptomatic uterine fibroids measuring less than 6 cm underwent laparoscopic ultrasound-guided radiofrequency ablation (RFA) using multiprobe-array electrodes. Follow-up of the treated fibroids was performed with gadolinium-enhanced magnetic resonance imaging (MRI) and patients' symptoms were assessed by telephone interviews. The procedure was initially technically successful in 3 of the 4 patients and MRI studies at 1 month demonstrated complete fibroid ablation. Symptom improvement, including a decrease in menstrual bleeding and pain, was achieved in 2 patients at 3 months. At 7 months, 1 of these 2 patients experienced symptom worsening which correlated with recurrent fibroid on MRI. The third, initially technically successfully treated patient did not experience any symptom relief after the procedure and was ultimately diagnosed with adenomyosis. Our preliminary results suggest that RFA is a technically feasible treatment for symptomatic uterine fibroids in appropriately selected patients.

  20. Kinetic equilibrium and relativistic thermodynamics

    E-Print Network [OSTI]

    P. Ván

    2011-02-01T23:59:59.000Z

    Relativistic thermodynamics is treated from the point of view of kinetic theory. It is shown that the generalized J\\"uttner distribution suggested in [1] is compatible with kinetic equilibrium. The requirement of compatibility of kinetic and thermodynamic equilibrium reveals several generalizations of the Gibbs relation where the velocity field is an independent thermodynamic variable.

  1. Laser microphone

    DOE Patents [OSTI]

    Veligdan, James T. (Manorville, NY)

    2000-11-14T23:59:59.000Z

    A microphone for detecting sound pressure waves includes a laser resonator having a laser gain material aligned coaxially between a pair of first and second mirrors for producing a laser beam. A reference cell is disposed between the laser material and one of the mirrors for transmitting a reference portion of the laser beam between the mirrors. A sensing cell is disposed between the laser material and one of the mirrors, and is laterally displaced from the reference cell for transmitting a signal portion of the laser beam, with the sensing cell being open for receiving the sound waves. A photodetector is disposed in optical communication with the first mirror for receiving the laser beam, and produces an acoustic signal therefrom for the sound waves.

  2. Diaphragmatic Hernia After Radiofrequency Ablation for Hepatocellular Carcinoma

    SciTech Connect (OSTI)

    Yamagami, Takuji, E-mail: yamagami@koto.kpu-m.ac.jp; Yoshimatsu, Rika; Matsushima, Shigenori; Tanaka, Osamu; Miura, Hiroshi; Nishimura, Tsunehiko [Kyoto Prefectural University of Medicine, Department of Radiology, Graduate School of Medical Science (Japan)

    2011-02-15T23:59:59.000Z

    We describe a 71-year-old woman with a hepatocellular carcinoma who underwent percutaneous radiofrequency ablation (RF) with a single internally cooled electrode under computed tomography (CT) fluoroscopic guidance. Nine months after the procedure, CT images showed herniation of the large intestine into the right pleural cavity. To our knowledge this complication of RF performed with a single internally cooled electrode under CT guidance has not been previously reported.

  3. Focal Hydrothermal Ablation: Preliminary Investigation of a New Concept

    SciTech Connect (OSTI)

    Roy, Sumit, E-mail: sumit.roy@online.no [Stavanger University Hospital, Department of Radiology (Norway)

    2013-08-01T23:59:59.000Z

    PurposeTo determine whether focal tissue ablation is possible with interstitial instillation of steam.MethodsFresh swine livers were used. Through a 20 gauge needle, steam was instilled every 5 s, 3 (n = 5), 6 (n = 5), 9 (n = 5), or 12 (n = 5 + 5) times in a liver lobe. The ablated zones were sectioned parallel (n = 20) or perpendicular (n = 5) to the needle track. The longitudinal long and short axis diameters, or transverse long and short axis diameters of areas with discoloration on macroscopic examination, were measured. The experiment was repeated in vivo on a pig. Steam instillation was performed once every 5 s for 5 min in the liver (n = 3) and in muscle (n = 4), and temperature changes at three neighboring sites were monitored. Long and short axis diameters of the discolored areas were measured.ResultsA well-defined area of discoloration was invariably present at the site of steam instillation. The median longitudinal long axis diameter were 2.0, 2.5, 2.5, and 3.5 cm for 3, 6, 9, and 12 steam instillations in vitro, while median short axis diameters were 1.0, 1.5, 1.5, and 1.5 cm, respectively. Six attempts at ablation in vivo could be successfully completed. The long axis diameters of the ablated zones in the liver were 7.0 and 8.0 cm, while in muscle it ranged from 5.5 to 7.0 cm.ConclusionInstillation of steam in the liver in vitro and in vivo, and in muscle in vivo rapidly leads to circumscribed zones of coagulation necrosis.

  4. Quality Improvement Guidelines for Radiofrequency Ablation of Liver Tumours

    SciTech Connect (OSTI)

    Crocetti, Laura, E-mail: l.crocetti@med.unipi.i [University of Pisa, Division of Diagnostic Imaging and Intervention, Department of Hepatology, Liver Transplants, and Infectious Diseases (Italy); Baere, Thierry de [Institut de Cancerologie Gustave Roussy, Department of Interventional Radiology (France); Lencioni, Riccardo [University of Pisa, Division of Diagnostic Imaging and Intervention, Department of Hepatology, Liver Transplants, and Infectious Diseases (Italy)

    2010-02-15T23:59:59.000Z

    The development of image-guided percutaneous techniques for local tumour ablation has been one of the major advances in the treatment of liver malignancies. Among these methods, radiofrequency ablation (RFA) is currently established as the primary ablative modality at most institutions. RFA is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma (HCC) when liver transplantation or surgical resection are not suitable options [1, 2]. In addition, RFA is considered a viable alternate to surgery (1) for inoperable patients with limited hepatic metastatic disease, especially from colorectal cancer, and (2) for patients deemed ineligible for surgical resection because of extent and location of the disease or concurrent medical conditions [3]. These guidelines were written to be used in quality-improvement programs to assess RFA of HCC and liver metastases. The most important processes of care are (1) patient selection, (2) performing the procedure, and (3) monitoring the patient. The outcome measures or indicators for these processes are indications, success rates, and complication rates.

  5. Improving alternative fuel utilization: detailed kinetic combustion...

    Energy Savers [EERE]

    Improving alternative fuel utilization: detailed kinetic combustion modeling & experimental testing Improving alternative fuel utilization: detailed kinetic combustion modeling &...

  6. Laser ignition

    DOE Patents [OSTI]

    Early, James W.; Lester, Charles S.

    2004-01-13T23:59:59.000Z

    Sequenced pulses of light from an excitation laser with at least two resonator cavities with separate output couplers are directed through a light modulator and a first polarzing analyzer. A portion of the light not rejected by the first polarizing analyzer is transported through a first optical fiber into a first ignitor laser rod in an ignitor laser. Another portion of the light is rejected by the first polarizing analyzer and directed through a halfwave plate into a second polarization analyzer. A first portion of the output of the second polarization analyzer passes through the second polarization analyzer to a second, oscillator, laser rod in the ignitor laser. A second portion of the output of the second polarization analyzer is redirected by the second polarization analyzer to a second optical fiber which delays the beam before the beam is combined with output of the first ignitor laser rod. Output of the second laser rod in the ignitor laser is directed into the first ignitor laser rod which was energized by light passing through the first polarizing analyzer. Combined output of the first ignitor laser rod and output of the second optical fiber is focused into a combustible fuel where the first short duration, high peak power pulse from the ignitor laser ignites the fuel and the second long duration, low peak power pulse directly from the excitation laser sustains the combustion.

  7. Thermal Ablation of Lung Tissue: In Vivo Experimental Comparison of Microwave and Radiofrequency

    SciTech Connect (OSTI)

    Crocetti, Laura, E-mail: l.crocetti@med.unipi.it; Bozzi, Elena [Pisa University Hospital, Division of Radiodiagnostic, Department of Oncological and Radiological Sciences (Italy); Faviana, Pinuccia [Pisa University Hospital, Division of Pathology, Department of Laboratory Medicine and Molecular Diagnostics (Italy); Cioni, Dania [Pisa University Hospital, Division of Diagnostic Imaging and Intervention, Department of Hepatology and Liver Transplantation (Italy); Della Pina, Clotilde [Pisa University Hospital, Division of Radiodiagnostic, Department of Oncological and Radiological Sciences (Italy); Sbrana, Alberto [University of Pisa (Italy); Fontanini, Gabriella [Pisa University Hospital, Division of Pathology, Department of Laboratory Medicine and Molecular Diagnostics (Italy); Lencioni, Riccardo [Pisa University Hospital, Division of Diagnostic Imaging and Intervention, Department of Hepatology and Liver Transplantation (Italy)

    2010-08-15T23:59:59.000Z

    This study was designed to compare feasibility, safety, and effectiveness of microwave (MW) ablation versus radiofrequency (RF) ablation of lung tissue in a rabbit model. Twenty New Zealand White rabbits were submitted to MW (n = 10, group A) or RF ablation (n = 10, group B). The procedures were performed with a prototype MW ablation device with a 1.6-cm radiating section antenna (Valleylab MW Ablation System) and with a 2-cm exposed-tip RF electrode (Cool-tip RF Ablation System). At immediate computed tomography increase in density, maximum diameters (D1-D3) of ablation zones were measured and ablation volume was calculated. Histopathologic assessment was performed 3 and 7 days after the procedure. Technical success was achieved in nine of 10 rabbits in each group. One death occurred in group B. Complications included pneumothorax (group A, n = 4; group B, n = 4), abscess (group A, n = 1; group B, n = 1), and thoracic wall burn (group A, n = 4). No significant differences were demonstrated in attenuation increase (P = 0.73), dimensions (P = 0.28, 0.86, 0.06, respectively, comparing D1-D3) and volume (P = 0.17). At histopathology, ablation zones were similar, with septal necrosis, edema, hemorrhage, and peripheral lymphocytic infiltrate. Complete thrombosis of more than 90% of vessels up to 2 mm in diameter was depicted at the periphery of the ablation zone in group A specimens. In group B specimens, complete thrombosis was depicted in 20% of vessels. Feasibility and safety of MW and RF ablation are similar in a lung rabbit model. MW ablation produces a greater damage to peripheral small vessels inducing thrombosis.

  8. Cosmological Kinetic Mixing

    E-Print Network [OSTI]

    Ashok Das; Jorge Gamboa; Miguel Pino

    2015-04-15T23:59:59.000Z

    In this paper we generalize the kinetic mixing idea to time reparametrization invariant theories, namely, relativistic point particles and cosmology in order to obtain new insights for dark matter and energy. In the first example, two relativistic particles interact through an appropriately chosen coupling term. It is shown that the system can be diagonalized by means of a non-local field redefinition, and, as a result of this procedure, the mass of one the particles gets rescaled. In the second case, inspired by the previous example, two cosmological models (each with its own scale factor) are made to interact in a similar fashion. The equations of motion are solved numerically in different scenarios (dust, radiation or a cosmological constant coupled to each sector of the system). When a cosmological constant term is present, kinetic mixing rescales it to a lower value which may be more amenable to observations.

  9. 474 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Fast Photography of a Laser Generated Plasma

    E-Print Network [OSTI]

    Harilal, S. S.

    . Bindhu, and F. Najmabadi Abstract--The dynamics and confinement of laser generated Carbon plumes. Photographic studies showed the collapse of the ablation plume after the bubble lifetime, and formation of two graphitic carbon plasmas expanding across a transverse magnetic field have been investigated using fast

  10. Elevated temperature ablation resistance of HfC particle-reinforced tungsten composites

    E-Print Network [OSTI]

    Hong, Soon Hyung

    and spark plasma sintering (SPS) process. HfC was chos Keywords: Composite materials Powder metallurgy Sintering Ablation properties Microstructure The effects

  11. ablation multi-collector inductively: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    mass spectrometry (ICP-MS). A compact computer Chen, Zhongxing 14 Measurements of Cavitation Dose, Echogenicity, and Temperature during Ultrasound Ablation Biology and Medicine...

  12. Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers

    SciTech Connect (OSTI)

    Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

    2009-12-16T23:59:59.000Z

    Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

  13. Laser device

    DOE Patents [OSTI]

    Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

    2007-07-10T23:59:59.000Z

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  14. Laser ignition

    DOE Patents [OSTI]

    Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

    2003-01-01T23:59:59.000Z

    In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In a third embodiment, alternating short and long pulses of light from the excitation light source are directed into the ignitor laser. Each of the embodiments of the invention can be multiplexed so as to provide laser light energy sequentially to more than one ignitor laser.

  15. Free-Electron Laser FLASH Injector Laser

    E-Print Network [OSTI]

    FLASH. Free-Electron Laser in Hamburg FLASH Injector Laser Laser 1 Laser 2 Next steps Siegfried | FLASH Meeting | 16-Nov-2009 FLASH. Free-Electron Laser in Hamburg Laser 1 System Overview fround trip A 541 (2005) 467­477 #12;Siegfried Schreiber | FLASH Meeting | 16-Nov-2009 FLASH. Free-Electron Laser

  16. Laser micro-processing of silicon using nanosecond pulse shaped fibre laser at 1 ?m wavelength

    E-Print Network [OSTI]

    Li, Kun

    2012-06-12T23:59:59.000Z

    ). ............................................................................... 11 Figure 2.2(a): Schematic and (b) SEM image of 19.8% efficient multicrystalline silicon solar cell with “honeycomb” surface texturing (Zhao, Wang et al. 1998). (c) The “inverted pyramid” texture on the top surface (Zhao, Wang et al. 1995). (d) A... is 40 µm (Tan 2006). (c): SEM image of silicon machined by frequency tripled Nd: YAG laser (355 nm) followed by cleaning in the KOH solution (Chen and Darling 2005). (d) Profiles and SEM images (×1.5 k) of ablated a-Si under different irradiation...

  17. Fully-automatic laser welding and micro-sculpting with universal in situ inline coherent imaging

    E-Print Network [OSTI]

    Webster, Paul J L; Ji, Yang; Galbraith, Christopher M; Kinross, Alison W; Van Vlack, Cole; Fraser, James M

    2014-01-01T23:59:59.000Z

    Though new affordable high power laser technologies make possible many processing applications in science and industry, depth control remains a serious technical challenge. Here we show that inline coherent imaging, with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration depth in a process as violent as kW-class keyhole welding. We exploit ICI's high speed, high dynamic range and robustness to interference from other optical sources to achieve fully automatic, adaptive control of laser welding as well as ablation, achieving micron-scale sculpting in vastly different heterogeneous biological materials.

  18. Kinetics of Oscillating Neutrinos

    E-Print Network [OSTI]

    P. Strack

    2005-05-12T23:59:59.000Z

    In the context of core-collapse supernovae, Strack and Burrows (Phys. Rev. D 71, 093004 (2005)) have recently developed an extension of the classical Boltzmann kinetic formalism that retains all the standard neutrino oscillation phenomenology, including resonant flavor conversion (the MSW effect), neutrino self-interactions, and the interplay between neutrino-matter coupling and flavor oscillations. In this thesis, I extend the Strack & Burrows formalism to incorporate general relativity, spin degrees of freedom, and a possible neutrino magnetic-moment/magnetic-field interaction.

  19. Chemical kinetics modeling

    SciTech Connect (OSTI)

    Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Laboratory, CA (United States)

    1993-12-01T23:59:59.000Z

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  20. Use of Semiflexible Applicators for Radiofrequency Ablation of Liver Tumors

    SciTech Connect (OSTI)

    Gaffke, G., E-mail: gunnar.gaffke@charite.de; Gebauer, B.; Knollmann, F.D. [Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde und Poliklinik, Charite (Germany); Helmberger, T. [Universitaet Muenchen, Institut fuer klinische Radiologie Grosshadern (Germany); Ricke, J. [Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde und Poliklinik, Charite (Germany); Oettle, H. [Universitaetsmedizin Berlin, Campus-Virchow-Klinikum, Medizinische Klinik mit Schwerpunkt Haematologie und Onkologie der Charite (Germany); Felix, R.; Stroszczynski, C. [Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde und Poliklinik, Charite (Germany)

    2006-04-15T23:59:59.000Z

    Purpose. To evaluate the feasibility and potential advantages of the radiofrequency ablation of liver tumors using new MRI-compatible semiflexible applicators in a closed-bore high-field MRI scanner. Methods. We treated 8 patients with 12 malignant liver tumors of different origin (5 colorectal carcinoma, 2 cholangiocellular carcinoma, 1 breast cancer) under MRI guidance. Radiofrequency ablation (RFA) was performed using 5 cm Rita Starburst Semi-Flex applicators (Rita Medical Systems, Milwaukee, WI, USA) which are suitable for MR- and CT-guided interventions and a 150 W RF generator. All interventions were performed in a closed-bore 1.5 T high-field MRI scanner for MRI-guided RFA using fast T1-weighted gradient echo sequences and T2-weighted ultra-turbo spin echo sequences. Control and follow-up MRI examinations were performed on the next day, at 6 weeks, and every 3 months after RFA. Control MRI were performed as double-contrast MRI examinations (enhancement with iron oxide and gadopentetate dimeglumine). All interventions were performed with the patient under local anesthesia and analgo-sedation. Results. The mean diameter of the treated hepatic tumors was 2.4 cm ({+-}0.6 cm, range 1.0-3.2 cm). The mean diameter of induced necrosis was 3.1 cm ({+-}0.4 cm). We achieved complete ablation in all patients. Follow-up examinations over a duration of 7 months ({+-}1.3 months, range 4-9 month) showed a local control rate of 100% in this group of patients. All interventions were performed without major complications; only 2 subcapsular hematomas were documented. Conclusion. RFA of liver tumors using semiflexible applicators in closed-bore 1.5 T scanner systems is feasible. These applicators might simplify the RFA of liver tumors under MRI control. The stiff distal part of the applicator facilitates its repositioning.

  1. EJECTA KNOT FLICKERING, MASS ABLATION, AND FRAGMENTATION IN CASSIOPEIA A

    SciTech Connect (OSTI)

    Fesen, Robert A.; Zastrow, Jordan A.; Hammell, Molly C. [6127 Wilder Laboratory, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Shull, J. Michael; Silvia, Devin W. [CASA, Department of Astrophysical and Planetary Science, University of Colorado, Boulder, CO 80309 (United States)

    2011-08-01T23:59:59.000Z

    Ejecta knot flickering, ablation tails, and fragmentation are expected signatures associated with the gradual dissolution of high-velocity supernova (SN) ejecta caused by their passage through an inhomogeneous circumstellar medium or interstellar medium (ISM). Such phenomena mark the initial stages of the gradual merger of SN ejecta with and the enrichment of the surrounding ISM. Here we report on an investigation of this process through changes in the optical flux and morphology of several high-velocity ejecta knots located in the outskirts of the young core-collapse SN remnant Cassiopeia A using Hubble Space Telescope images. Examination of WFPC2 F675W and combined ACS F625W + F775W images taken between 1999 June and 2004 December of several dozen debris fragments in the remnant's northeast ejecta stream and along the remnant's eastern limb reveal substantial emission variations ('flickering') over timescales as short as nine months. Such widespread and rapid variability indicates knot scale lengths {approx_equal} 10{sup 15} cm and a highly inhomogeneous surrounding medium. We also identify a small percentage of ejecta knots located all around the remnant's outer periphery which show trailing emissions typically 0.''2-0.''7 in length aligned along the knot's direction of motion suggestive of knot ablation tails. We discuss the nature of these trailing emissions as they pertain to ablation cooling, knot disruption, and fragmentation, and draw comparisons to the emission 'strings' seen in {eta} Car. Finally, we identify several tight clusters of small ejecta knots which resemble models of shock-induced fragmentation of larger SN ejecta knots caused by a high-velocity interaction with a lower density ambient medium.

  2. Influence of Radiofrequency Ablation of Lung Cancer on Pulmonary Function

    SciTech Connect (OSTI)

    Tada, Akihiro, E-mail: tdakihiro@gmail.com; Hiraki, Takao [Okayama University Medical School, Department of Radiology (Japan); Iguchi, Toshihiro [Fukuyama City Hospital, Department of Radiology (Japan); Gobara, Hideo; Mimura, Hidefumi [Okayama University Medical School, Department of Radiology (Japan); Toyooka, Shinichi [Okayama University Medical School, Department of Cancer and Thoracic Surgery (Japan); Kiura, Katsuyuki [Okayama University Medical School, Department of Respiratory Medicine (Japan); Tsuda, Toshihide [Okayama University Graduate School, Department of Environmental Epidemiology, Graduate School of Environmental Science (Japan); Mitsuhashi, Toshiharu [Okayama University Medical School, Department of Epidemiology (Japan); Kanazawa, Susumu [Okayama University Medical School, Department of Radiology (Japan)

    2012-08-15T23:59:59.000Z

    Purpose: The purpose of this study was to evaluate altered pulmonary function retrospectively after RFA. Methods: This retrospective study comprised 41 ablation sessions for 39 patients (22 men and 17 women; mean age, 64.8 years). Vital capacity (VC) and forced expiratory volume in 1 s (FEV{sub 1}) at 1 and 3 months after RFA were compared with the baseline (i.e., values before RFA). To evaluate the factors that influenced impaired pulmonary function, univariate analysis was performed by using multiple variables. If two or more variables were indicated as statistically significant by univariate analysis, these variables were subjected to multivariate analysis to identify independent factors. Results: The mean VC and FEV{sub 1} before RFA and 1 and 3 months after RFA were 3.04 and 2.24 l, 2.79 and 2.11 l, and 2.85 and 2.13 l, respectively. The values at 1 and 3 months were significantly lower than the baseline. Severe pleuritis after RFA was identified as the independent factor influencing impaired VC at 1 month (P = 0.003). For impaired FEV{sub 1} at 1 month, only severe pleuritis (P = 0.01) was statistically significant by univariate analysis. At 3 months, severe pleuritis (VC, P = 0.019; FEV{sub 1}, P = 0.003) and an ablated parenchymal volume {>=}20 cm{sup 3} (VC, P = 0.047; FEV{sub 1}, P = 0.038) were independent factors for impaired VC and FEV{sub 1}. Conclusions: Pulmonary function decreased after RFA. RFA-induced severe pleuritis and ablation of a large volume of marginal parenchyma were associated with impaired pulmonary function.

  3. Palliative Treatment of Rectal Carcinoma Recurrence Using Radiofrequency Ablation

    SciTech Connect (OSTI)

    Mylona, Sophia, E-mail: mylonasophia@yahoo.com; Karagiannis, Georgios, E-mail: gekaragiannis@yahoo.gr; Patsoura, Sofia, E-mail: sofia.patsoura@yahoo.gr [Hellenic Red Cross Hospital 'Korgialenio-Benakio' (Greece); Galani, Panagiota, E-mail: gioulagalani@yahoo.com [Amalia Fleming Hospital (Greece); Pomoni, Maria, E-mail: marypomoni@gmail.com [Evgenidion Hospital (Greece); Thanos, Loukas, E-mail: loutharad@yahoo.com [Sotiria Hospital (Greece)

    2012-08-15T23:59:59.000Z

    Purpose: To evaluate the safety and efficacy of CT-guided radiofrequency (RF) ablation for the palliative treatment of recurrent unresectable rectal tumors. Materials and Methods: Twenty-seven patients with locally recurrent rectal cancer were treated with computed tomography (CT)-guided RF ablation. Therapy was performed with the patient under conscious sedation with a seven- or a nine-array expandable RF electrode for 8-10 min at 80-110 Degree-Sign C and a power of 90-110 W. All patients went home under instructions the next day of the procedure. Brief Pain Inventory score was calculated before and after (1 day, 1 week, 1 month, 3 months, and 6 months) treatment. Results: Complete tumor necrosis rate was 77.8% (21 of a total 27 procedures) despite lesion location. BPI score was dramatically decreased after the procedure. The mean preprocedure BPI score was 6.59, which decreased to 3.15, 1.15, and 0.11 at postprocedure day 1, week 1, and month 1, respectively, after the procedure. This decrease was significant (p < 0.01 for the first day and p < 0.001 for the rest of the follow-up intervals (paired Student t test; n - 1 = 26) for all periods during follow-up. Six patients had partial tumor necrosis, and we were attempted to them with a second procedure. Although the necrosis area showed a radiographic increase, no complete necrosis was achieved (secondary success rate 65.6%). No immediate or delayed complications were observed. Conclusion: CT-guided RF ablation is a minimally invasive, safe, and highly effective technique for treatment of malignant rectal recurrence. The method is well tolerated by patients, and pain relief is quickly achieved.

  4. IDetachable, Human-Rated, Ablative Environmentally Compliant TPSLunar Surface Systems 2008 Phase II

    E-Print Network [OSTI]

    Systems 2008 Phase II Proposal X8.01-8631 Lightweight Hybrid Ablator Incorporating Aerogel-Filled Open skeleton filled with a high temperature nanoscale aerogel insulator. Structural integrity and high insulation behavior have been demonstrated when used in combination with a non-ablating, coated carbon

  5. Massive Hemoptysis from Pulmonary Artery Pseudoaneurysm Caused by Lung Radiofrequency Ablation: Successful Treatment by Coil Embolization

    SciTech Connect (OSTI)

    Yamakado, Koichiro, E-mail: yama@clin.medic.mie-u.ac.jp; Takaki, Haruyuki [Mie University School of Medicine, Department of Radiology (Japan); Takao, Motoshi [Mie University School of Medicine, Department of Thoracic Surgery (Japan); Murashima, Shuichi; Kodama, Hiroshi; Kashima, Masataka; Nakatsuka, Atsuhiro; Uraki, Junji [Mie University School of Medicine, Department of Radiology (Japan); Shimpo, Hideto [Mie University School of Medicine, Department of Thoracic Surgery (Japan); Takeda, Kan [Mie University School of Medicine, Department of Radiology (Japan)

    2010-04-15T23:59:59.000Z

    A 75-year-old man received lung radiofrequency (RF) ablation to treat lung metastases from hepatocellular carcinoma. Massive hemoptysis occurred 1 week after lung RF ablation. Emergent contrast-enhanced CT and pulmonary arteriography revealed a pulmonary artery pseudoaneurysm, which was embolized with coils. The postembolization course was uneventful. Hemoptysis did not recur for 5 months.

  6. Radiofrequency Ablation Treatment in Proximity to the Gallbladder Without Subsequent Acute Cholecystitis

    SciTech Connect (OSTI)

    Patti, Jay W.; Neeman, Ziv, E-mail: zneeman@cc.hih.gov; Wood, Bradford J. [National Institutes of Health Clinical Center, Building 10, Room 1C641, Bethesda, MD 20892 (United States)

    2003-08-15T23:59:59.000Z

    Initial reports have suggested that proximity of liver tumors to the gallbladder may increase the risk for cholecystitis after radiofrequency ablation. A colon adenocarcinoma metastasis to the liver in contact with the gallbladder was successfully treated with radiofrequency ablation without subsequent cholecystitis.

  7. Imaging of lithium pellet ablation trails and measurement of g profiles in TFTR

    E-Print Network [OSTI]

    Garnier, Darren T.

    Imaging of lithium pellet ablation trails and measurement of g profiles in TFTR J. L. Terry, E. S March 1992) Video images with 2 ps exposures of the Li+ emission in Li pellet ablation clouds have been obtained in a variety of Tokamak Fusion Test Reactor tokamak discharges. The pellet clouds are viewed from

  8. Snow ablation modelling in a mature aspen stand of the boreal forest

    E-Print Network [OSTI]

    Ni-Meister, Wenge

    Snow ablation modelling in a mature aspen stand of the boreal forest J. P. Hardy,1* R. E. Davis,1 R- ing snow ablation in a lea¯ess, deciduous aspen stand and verifying the results with ®eld data. New to estimate a branch area index for defoliated aspen as an analogue to the foliage area index used

  9. Laser-induced breakdown spectroscopy of tantalum plasma

    SciTech Connect (OSTI)

    Khan, Sidra; Bashir, Shazia; Hayat, Asma; Khaleeq-ur-Rahman, M.; Faizan–ul-Haq [Centre for Advanced Studies in Physics, GC University, Lahore (Pakistan)] [Centre for Advanced Studies in Physics, GC University, Lahore (Pakistan)

    2013-07-15T23:59:59.000Z

    Laser Induced Breakdown spectroscopy (LIBS) of Tantalum (Ta) plasma has been investigated. For this purpose Q-switched Nd: YAG laser pulses (?? 1064 nm, ?? 10 ns) of maximum pulse energy of 100 mJ have been employed as an ablation source. Ta targets were exposed under the ambient environment of various gases of Ar, mixture (CO{sub 2}: N{sub 2}: He), O{sub 2}, N{sub 2}, and He under various filling pressure. The emission spectrum of Ta is observed by using LIBS spectrometer. The emission intensity, excitation temperature, and electron number density of Ta plasma have been evaluated as a function of pressure for various gases. Our experimental results reveal that the optical emission intensity, the electron temperature and density are strongly dependent upon the nature and pressure of ambient environment. The SEM analysis of the ablated Ta target has also been carried out to explore the effect of ambient environment on the laser induced grown structures. The growth of grain like structures in case of molecular gases and cone-formation in case of inert gases is observed. The evaluated plasma parameters by LIBS analysis such as electron temperature and the electron density are well correlated with the surface modification of laser irradiated Ta revealed by SEM analysis.

  10. Pulmonary Artery Pseudoaneurysm Related to Radiofrequency Ablation of Lung Tumor

    SciTech Connect (OSTI)

    Sakurai, Jun, E-mail: sakurai@cc.okayama-u.ac.jp; Mimura, Hidefumi; Gobara, Hideo; Hiraki, Takao; Kanazawa, Susumu [Okayama University Medical School, Department of Radiology (Japan)

    2010-04-15T23:59:59.000Z

    We describe a case of pulmonary artery (PA) pseudoaneurysm related to radiofrequency ablation (RFA) of lung tumor. We performed RFA for a pulmonary epithelioid hemangioendothelioma directly adjacent to a branch of the PA. Seventeen days later, the patient complained of hemoptysis. A chest CT image revealed PA pseudoaneurysm. Transcatheter coil embolization was performed 59 days after RFA. Although PA pseudoaneurysm is rare, with an incidence of 0.2% (1/538 sessions) at our institution, it should be recognized as a risk when treating lung tumors adjacent to a branch of the PA.

  11. Biocavity Lasers

    SciTech Connect (OSTI)

    Gourley, P.L.; Gourley, M.F.

    2000-10-05T23:59:59.000Z

    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  12. Laser ignition

    DOE Patents [OSTI]

    Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

    2002-01-01T23:59:59.000Z

    In the apparatus of the invention, a first excitation laser or other excitation light source capable of producing alternating beams of light having different wavelengths is used in tandem with one or more ignitor lasers to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using the single remote excitation light source for pumping one or more small lasers located proximate to one or more fuel combustion zones with alternating wavelengths of light.

  13. ablated plasma width: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    proposed simple kinetic model for a sequential decay of heavy QGP bags formed in high energy elementary particle collisions it is argued that by measuring the energy dependence of...

  14. Ambient gas effects on the dynamics of laser-produced tin plume expansion

    E-Print Network [OSTI]

    Harilal, S S; O'Shay, B; Tillac, M S; Tao, Y

    2006-01-01T23:59:59.000Z

    mitigation in a laser-produced tin plasma is one of the mostambient pressure, the tin species with kinetic Downloaded 19Sn + species ejected by the tin plume exhibits a Downloaded

  15. Task 12: Laser cleaning of contaminated painted surfaces. Semi-annual report, April 1, 1996--September 30, 1996

    SciTech Connect (OSTI)

    Grisanti, A.A.; Hassett, D.J.

    1997-05-01T23:59:59.000Z

    Paint contaminated with radionuclides and other hazardous materials is common in Department of Energy (DOE) facilities. Facility decommissioning and decontamination requires the removal of contaminated paint. Paint removal technologies include laser- and abrasive-based systems. F2 Associates are utilizing a pulsed-repetition CO{sub 2} laser that produces a 2.5-cm x 2.5-cm beam which can be scanned across a 30- x 100-cm raster and, when placed on a robot, can be designed to clean any surface that the robot can be programmed to follow. Causing little or no damage to the substrate (concrete, steel, etc.), the laser ablates the material to be removed from a given surface. Ablated material is then pulled into a filtration and collection (VAC-PAC) system to prevent the hazardous substances from entering into the atmosphere. The VAC-PAC system deposits the ablated material into waste drums which may be removed from the system without compromising the integrity of the seal, allowing a new drum to be set up for collection without leakage of the ablated material into the atmosphere.

  16. Method for materials deposition by ablation transfer processing

    DOE Patents [OSTI]

    Weiner, K.H.

    1996-04-16T23:59:59.000Z

    A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs. 1 fig.

  17. Method for materials deposition by ablation transfer processing

    DOE Patents [OSTI]

    Weiner, Kurt H. (San Jose, CA)

    1996-01-01T23:59:59.000Z

    A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs.

  18. Dimensional enhancement of kinetic energies

    E-Print Network [OSTI]

    W. P. Schleich; J. P. Dahl

    2002-03-14T23:59:59.000Z

    Simple thermodynamics considers kinetic energy to be an extensive variable which is proportional to the number, N, of particles. We present a quantum state of N non-interacting particles for which the kinetic energy increases quadratically with N. This enhancement effect is tied to the quantum centrifugal potential whose strength is quadratic in the number of dimensions of configuration space.

  19. Interpretation of time-of-flight distributions for neutral particles under pulsed laser evaporation using direct Monte Carlo simulation

    SciTech Connect (OSTI)

    Morozov, Alexey A., E-mail: morozov@itp.nsc.ru [Institute of Thermophysics SB RAS, 1 Lavrentyev Ave., 630090 Novosibirsk (Russian Federation)

    2013-12-21T23:59:59.000Z

    A theoretical study of the time-of-flight (TOF) distributions under pulsed laser evaporation in vacuum has been performed. A database of TOF distributions has been calculated by the direct simulation Monte Carlo (DSMC) method. It is shown that describing experimental TOF signals through the use of the calculated TOF database combined with a simple analysis of evaporation allows determining the irradiated surface temperature and the rate of evaporation. Analysis of experimental TOF distributions under laser ablation of niobium, copper, and graphite has been performed, with the evaluated surface temperature being well agreed with results of the thermal model calculations. General empirical dependences are proposed, which allow indentifying the regime of the laser induced thermal ablation from the TOF distributions for neutral particles without invoking the DSMC-calculated database.

  20. Ultrafast electron beam imaging of femtosecond laser-induced plasma Junjie Li, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao et al.

    E-Print Network [OSTI]

    Cao, Jianming

    , Beijing 100190, China and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast have been a subject of intensive investigation in recent years ow- ing to its importance in a wide

  1. High-frequency electromagnetic properties of epitaxial Bi2FeCrO6 thin films grown by pulsed laser deposition

    E-Print Network [OSTI]

    High-frequency electromagnetic properties of epitaxial Bi2FeCrO6 thin films grown by pulsed laser on the electromagnetic (EM) properties in high-frequency domain (HF) of multiferroic Bi2FeCrO6 (BFCO) thin films. The films were epitaxially grown on SrTiO3 substrates by pulsed laser ablation. Typical 50 nm-thick BFCO

  2. Percutaneous Irreversible Electroporation Lung Ablation: Preliminary Results in a Porcine Model

    SciTech Connect (OSTI)

    Deodhar, Ajita [Memorial Sloan Kettering Cancer Center, Interventional Radiology and Image-Guided Therapies (United States); Monette, Sebastien [Memorial Sloan Kettering Cancer Center, Laboratory of Comparative Pathology (United States); Single, Gordon W.; Hamilton, William C. [Angiodynamics, Inc (United States); Thornton, Raymond H.; Sofocleous, Constantinos T.; Maybody, Majid; Solomon, Stephen B., E-mail: solomons@mskcc.org [Memorial Sloan Kettering Cancer Center, Interventional Radiology and Image-Guided Therapies (United States)

    2011-12-15T23:59:59.000Z

    Objective: Irreversible electroporation (IRE) uses direct electrical pulses to create permanent 'pores' in cell membranes to cause cell death. In contrast to conventional modalities, IRE has a nonthermal mechanism of action. Our objective was to study the histopathological and imaging features of IRE in normal swine lung. Materials and Methods: Eleven female swine were studied for hyperacute (8 h), acute (24 h), subacute (96 h), and chronic (3 week) effects of IRE ablation in lung. Paired unipolar IRE applicators were placed under computed tomography (CT) guidance. Some applicators were deliberately positioned near bronchovascular structures. IRE pulse delivery was synchronized with the cardiac rhythm only when ablation was performed within 2 cm of the heart. Contrast-enhanced CT scan was performed immediately before and after IRE and at 1 and 3 weeks after IRE ablation. Representative tissue was stained with hematoxylin and eosin for histopathology. Results: Twenty-five ablations were created: ten hyperacute, four acute, and three subacute ablations showed alveolar edema and necrosis with necrosis of bronchial, bronchiolar, and vascular epithelium. Bronchovascular architecture was maintained. Chronic ablations showed bronchiolitis obliterans and alveolar interstitial fibrosis. Immediate post-procedure CT images showed linear or patchy density along the applicator tract. At 1 week, there was consolidation that resolved partially or completely by 3 weeks. Pneumothorax requiring chest tube developed in two animals; no significant cardiac arrhythmias were noted. Conclusion: Our preliminary porcine study demonstrates the nonthermal and extracellular matrix sparing mechanism of action of IRE. IRE is a potential alternative to thermal ablative modalities.

  3. X-ray ablation rates in inertial confinement fusion capsule materials

    SciTech Connect (OSTI)

    Olson, R. E.; Rochau, G. A.; Leeper, R. J. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Landen, O. L. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2011-03-15T23:59:59.000Z

    X-ray ablation rates have been measured in beryllium, copper-doped beryllium, germanium-doped plastic (Ge-doped CH), and diamondlike high density carbon (HDC) for radiation temperatures T in the range of 160-260 eV. In beryllium, the measured ablation rates range from 3 to 12 mg/cm{sup 2}/ns; in Ge-doped CH, the ablation rates range from 2 to 6 mg/cm{sup 2}/ns; and for HDC, the rates range from 2 to 9 mg/cm{sup 2}/ns. The ablation rates follow an approximate T{sup 3} dependence and, for T below 230 eV, the beryllium ablation rates are significantly higher than HDC and Ge-doped CH. The corresponding implied ablation pressures are in the range of 20-160 Mbar, scaling as T{sup 3.5}. The results are found to be well predicted by computational simulations using the physics packages and computational techniques employed in the design of indirect-drive inertial confinement fusion capsules. An iterative rocket model has been developed and used to compare the ablation rate data set to spherical indirect-drive capsule implosion experiments and to confirm the validity of some aspects of proposed full-scale National Ignition Facility ignition capsule designs.

  4. High-throughput metal nanoparticle catalysis by pulsed laser ablation Selim Senkan a,*, Michael Kahn a

    E-Print Network [OSTI]

    Senkan, Selim M.

    of propylene. In less than a day, over 40 different catalytic materials of nanoparticles supported on g-Al2O3 oxidation products of propylene with one-pass yields of about 13% at 275 8C. # 2006 Published by Elsevier B of propylene oxide from propylene, hydrogen and oxygen [5]. On the other hand, larger Au nanoparticles result

  5. Characteristics and diagnostics of an ultrahigh vacuum compatible laser ablation source for crossed molecular beam experiments

    E-Print Network [OSTI]

    Kaiser, Ralf I.

    to their high carcinogenic risk potential. PAHs and carbonaceous nanoparticles are also serious water pollutants the formation of polycyclic aromatic hydrocar- bons PAHs , their hydrogen deficient precursors, and of car and bioaccumulate in the fatty tissue of living organisms. Together with leafy vegetables, where PAHs and soot

  6. Polymer Stable Magnesium Nanocomposites Prepared by Laser Ablation for Efficient Hydrogen Storage

    E-Print Network [OSTI]

    Makridis, S S; Panagakos, G; Kikkinides, E S; Stubos, A K; Wagener, P; Barcikowski, S

    2013-01-01T23:59:59.000Z

    Hydrogen is a promising alternative energy carrier that can potentially facilitate the transition from fossil fuels to sources of clean energy because of its prominent advantages such as high energy density (142 MJ per kg), great variety of potential sources (for example water, biomass, organic matter), and low environmental impact (water is the sole combustion product). However, due to its light weight, the efficient storage of hydrogen is still an issue investigated intensely. Various solid media have been considered in that respect among which magnesium hydride stands out as a candidate offering distinct advantages. Recent theoretical work indicates that MgH2 becomes less thermodynamically stable as particle diameter decreases below 2 nm. Our DFT (density functional theory) modeling studies have shown that the smallest enthalpy change, corresponding to 2 unit-cell thickness (1.6 {\\AA} Mg/3.0{\\AA} MgH2) of the film, is 57.7 kJ/molMg. This enthalpy change is over 10 kJ per molMg smaller than that of the bulk...

  7. A double tweezers and laser ablation (scissors) microscope for biological studies

    E-Print Network [OSTI]

    Parsa, Shahab

    2010-01-01T23:59:59.000Z

    culture fluid to a 15-ml centrifuge tube. Add 1-2 ml EBSS toPour this rinse into your centrifuge tube. Add 1-2 ml ATV tocoated. Pour ATV into centrifuge tube, leaving a tiny amount

  8. Laser Ablation Synthesis and Electron Transport Studies of Tin Oxide Nanowires**

    E-Print Network [OSTI]

    Zhou, Chongwu

    and solar cells.[7±9] In addition, SnO2 thin films have been extensively studied and used as chemical-dimensional metal oxide nanowires, such as In2O3,[1] ZnO,[2] SnO2,[3] CdO,[4] and CuO[5] nanowires, have attracted

  9. Glass particles produced by laser ablation for ICP-MS measurements

    E-Print Network [OSTI]

    Gonzalez, J.; Liu, C.; Wen, S.; Mao, X.; Russo, R.E.

    2008-01-01T23:59:59.000Z

    NIST) and X-ray fluorescence (XRF) monitor samples from Glenstandards), and figure 2 (XRF standards). The error barsand 160 and 180 nm for XRF monitor samples. These data show

  10. Improvements to Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh School footballHydrogenITLaboratory in Inductively Coupledfor

  11. Oxygen-assisted multipass cutting of carbon fiber reinforced plastics with ultra-short laser pulses

    SciTech Connect (OSTI)

    Kononenko, T. V.; Komlenok, M. S.; Konov, V. I. [Natural Sciences Center, General Physics Institute, Vavilov str. 38, 119991 Moscow (Russian Federation); National Research Nuclear University, “MEPhI,” Kashirskoye shosse 31, 115409 Moscow (Russian Federation); Freitag, C. [Universität Stuttgart, Institut für Strahlwerkzeuge (IFSW), Pfaffenwaldring 43, 70569 Stuttgart (Germany); GSaME Graduate School of Excellence Advanced Manufacturing Engineering, Nobelstrasse 12, 70569 Stuttgart (Germany); Onuseit, V.; Weber, R.; Graf, T. [Universität Stuttgart, Institut für Strahlwerkzeuge (IFSW), Pfaffenwaldring 43, 70569 Stuttgart (Germany)

    2014-03-14T23:59:59.000Z

    Deep multipass cutting of bidirectional and unidirectional carbon fiber reinforced plastics (CFRP) with picosecond laser pulses was investigated in different static atmospheres as well as with the assistance of an oxygen or nitrogen gas flow. The ablation rate was determined as a function of the kerf depth and the resulting heat affected zone was measured. An assisting oxygen gas flow is found to significantly increase the cutting productivity, but only in deep kerfs where the diminished evaporative ablation due to the reduced laser fluence reaching the bottom of the kerf does not dominate the contribution of reactive etching anymore. Oxygen-supported cutting was shown to also solve the problem that occurs when cutting the CFRP parallel to the fiber orientation where a strong deformation and widening of the kerf, which temporarily slows down the process speed, is revealed to be typical for processing in standard air atmospheres.

  12. Process for ion-assisted laser deposition of biaxially textured layer on substrate

    DOE Patents [OSTI]

    Russo, Richard E. (Walnut Creek, CA); Reade, Ronald P. (Berkeley, CA); Garrison, Stephen M. (Palo Alto, CA); Berdahl, Paul (Oakland, CA)

    1995-01-01T23:59:59.000Z

    A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film.

  13. Process for ion-assisted laser deposition of biaxially textured layer on substrate

    DOE Patents [OSTI]

    Russo, R.E.; Reade, R.P.; Garrison, S.M.; Berdahl, P.

    1995-07-11T23:59:59.000Z

    A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film. 8 figs.

  14. Multidimensional simulation and chemical kinetics development...

    Broader source: Energy.gov (indexed) [DOE]

    Developing chemical kinetic mechanisms and applying them to simulating engine combustion processes. deer09aceves.pdf More Documents & Publications Chemical Kinetic Research on...

  15. Direct Observation of Aggregative Nanoparticle Growth: Kinetic...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Aggregative Nanoparticle Growth: Kinetic Modeling of the Size Distribution and Growth Rate. Direct Observation of Aggregative Nanoparticle Growth: Kinetic Modeling of the Size...

  16. Temperature Independent Physisorption Kinetics and Adsorbate...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Temperature Independent Physisorption Kinetics and Adsorbate Layer Compression for Ar Adsorbed on Pt (111). Temperature Independent Physisorption Kinetics and Adsorbate Layer...

  17. thermodynamics kinetics | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    its kinetic behavior is more complex. Very little reliable kinetic information on coal gasification reactions exists, partly because it is highly depended on the process...

  18. Survival after Radiofrequency Ablation in 122 Patients with Inoperable Colorectal Lung Metastases

    SciTech Connect (OSTI)

    Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Radiology Department (United Kingdom); Khan, Zahid [Countess of Chester Hospital (United Kingdom); Osborn, Peter [Queen Alexandra Hospital (United Kingdom); Lees, William [University College London Medical School (United Kingdom)

    2013-06-15T23:59:59.000Z

    Purpose. To analyze the factors associated with favorable survival in patients with inoperable colorectal lung metastases treated with percutaneous image-guided radiofrequency ablation. Methods. Between 2002 and 2011, a total of 398 metastases were ablated in 122 patients (87 male, median age 68 years, range 29-90 years) at 256 procedures. Percutaneous CT-guided cool-tip radiofrequency ablation was performed under sedation/general anesthesia. Maximum tumor size, number of tumors ablated, number of procedures, concurrent/prior liver ablation, previous liver or lung resection, systemic chemotherapy, disease-free interval from primary resection to lung metastasis, and survival from first ablation were recorded prospectively. Kaplan-Meier analysis was performed, and factors were compared by log rank test. Results. The initial number of metastases ablated was 2.3 (range 1-8); the total number was 3.3 (range 1-15). The maximum tumor diameter was 1.7 (range 0.5-4) cm, and the number of procedures was 2 (range 1-10). The major complication rate was 3.9 %. Overall median and 3-year survival rate were 41 months and 57 %. Survival was better in patients with smaller tumors-a median of 51 months, with 3-year survival of 64 % for tumors 2 cm or smaller versus 31 months and 44 % for tumors 2.1-4 cm (p = 0.08). The number of metastases ablated and whether the tumors were unilateral or bilateral did not affect survival. The presence of treated liver metastases, systemic chemotherapy, or prior lung resection did not affect survival. Conclusion. Three-year survival of 57 % in patients with inoperable colorectal lung metastases is better than would be expected with chemotherapy alone. Patients with inoperable but small-volume colorectal lung metastases should be referred for ablation.

  19. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    SciTech Connect (OSTI)

    Skolski, J. Z. P., E-mail: j.z.p.skolski@utwente.nl; Vincenc Obona, J. [Materials innovation institute M2i, Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Römer, G. R. B. E.; Huis in 't Veld, A. J. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2014-03-14T23:59:59.000Z

    A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.

  20. Laser goniometer

    DOE Patents [OSTI]

    Fairer, George M. (Boulder, CO); Boernge, James M. (Lakewood, CO); Harris, David W. (Lakewood, CO); Campbell, DeWayne A. (Littleton, CO); Tuttle, Gene E. (Littleton, CO); McKeown, Mark H. (Golden, CO); Beason, Steven C. (Lakewood, CO)

    1993-01-01T23:59:59.000Z

    The laser goniometer is an apparatus which permits an operator to sight along a geologic feature and orient a collimated lamer beam to match the attitude of the feature directly. The horizontal orientation (strike) and the angle from horizontal (dip), are detected by rotary incremental encoders attached to the laser goniometer which provide a digital readout of the azimuth and tilt of the collimated laser beam. A microprocessor then translates the square wave signal encoder outputs into an ASCII signal for use by data recording equipment.

  1. Laser ablative fabrication of nanocrowns and nanojets on the Cu supported film surface using femtosecond laser pulses

    E-Print Network [OSTI]

    Kuchmizhak, A A; Vitrik, O B; Kulchin, Yu N

    2015-01-01T23:59:59.000Z

    Formation dynamics of the nanojets and nanocrowns induced on the surface of the Cu supported films of different thickness under the impact of tightly focused femtosecond pulses was studied in detail. We show that the single-shot fs-pulse irradiation of the 120-nm-thick Cu film results in formation of a single nanojet, which splits at increased pulse energy into two and then into a plurality of periodically arranged nanospikes eventually acquiring the form of the so-called nanocrown. The number of nanospike in the nanocrown was found to be linearly dependent on the pulse energy and nanocrown radius. The key role of subsurface boiling occurring on the metal film-substrate interface in the formation process of crown-like nanostructures was revealed by comparing the obtained results with the formation dynamics studied for thinner 60-nm and 20-nm-thick Cu films. In addition, the applicability of the fabricated nanostructures as low-cost substrate for photoluminescence signal enhancement of the organic dyes is also...

  2. Transhepatic Approach for Percutaneous Computed-Tomography-Guided Radiofrequency Ablation of Renal Cell Carcinoma

    SciTech Connect (OSTI)

    Iguchi, Toshihiro, E-mail: iguchi@cc.okayama-u.ac.jp; Hiraki, Takao; Gobara, Hideo; Mukai, Takashi; Hase, Soichiro; Fujiwara, Hiroyasu; Tajiri, Nobuhisa; Sakurai, Jun; Mimura, Hidefumi [Okayama University Medical School, Department of Radiology (Japan); Saika, Takashi; Kumon, Hiromi [Okayama University Medical School, Department of Urology (Japan); Kanazawa, Susumu [Okayama University Medical School, Department of Radiology (Japan)

    2007-07-15T23:59:59.000Z

    We performed percutaneously radiofrequency (RF) ablation of 5 renal cell carcinomas (mean diameter 26 {+-} 15 mm) with computed-tomography (CT) fluoroscopic guidance using the transhepatic route. The RF electrode was successfully advanced into all tumors. RF ablation caused one minor complication (small asymptomatic perirenal hematoma); no major complications occurred. The follow-up contrast-enhanced CT images showed no local tumor progression of any tumors in a median period of 10 months (range 3-14 months). In conclusion, it seems that this transhepatic approach is safe and can be an alternative method for electrode insertion during RF ablation of selected renal tumors.

  3. Percutaneous Radiofrequency Ablation for Treatment of Recurrent Retroperitoneal Liposarcoma

    SciTech Connect (OSTI)

    Keil, Sebastian, E-mail: keil@rad.rwth-aachen.de; Bruners, Philipp [RWTH Aachen University, Department of Diagnostic Radiology, University Hospital (Germany); Brehmer, Bernhard [RWTH Aachen University, Department of Urology, University Hospital (Germany); Mahnken, Andreas Horst [RWTH Aachen University, Department of Diagnostic Radiology, University Hospital (Germany)

    2008-07-15T23:59:59.000Z

    Percutaneous CT-guided radiofrequency ablation (RFA) is becoming more and more established in the treatment of various neoplasms, including retroperitoneal tumors of the kidneys and the adrenal glands. We report the case of RFA in a patient suffering from the third relapse of a retroperitoneal liposarcoma in the left psoas muscle. After repeated surgical resection and supportive radiation therapy of a primary retroperitoneal liposarcoma and two surgically treated recurrences, including replacement of the ureter by a fraction of the ileum, there was no option for further surgery. Thus, we considered RFA as the most suitable treatment option. Monopolar RFA was performed in a single session with a 2-cm umbrella-shaped LeVeen probe. During a 27-month follow-up period the patient remained free of tumor.

  4. Laser Optomechanics

    E-Print Network [OSTI]

    Yang, Weijian; Ng, Kar Wei; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J

    2015-01-01T23:59:59.000Z

    Cavity optomechanics explores the coupling between the optical field and the mechanical oscillation to induce cooling and regenerative oscillation in a mechanical oscillator. So far, optomechanics relies on the detuning between the cavity and an external pump laser, where the laser acts only as a power supply. Here, we report a new scheme with mutual coupling between a mechanical oscillator that supports a mirror of a vertical-cavity surface-emitting laser (VCSEL) and the optical field, greatly enhancing the light-matter energy transfer. In this work, we used an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror in a VCSEL, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity with > 550 nm self-oscillation amplitude of the micro-mechanical oscillator, two to three orders of magnitude larger than typical. This new scheme not only offers an efficient approach for high-...

  5. Laser barometer

    SciTech Connect (OSTI)

    Abercrombie, K.R.; Shiels, D.; Rash, T.

    1998-04-01T23:59:59.000Z

    This paper describes an invention of a pressure measuring instrument which uses laser radiation to sense the pressure in an enclosed environment by means of measuring the change in refractive index of a gas - which is pressure dependent.

  6. Outcome after Radiofrequency Ablation of Sarcoma Lung Metastases

    SciTech Connect (OSTI)

    Koelblinger, Claus, E-mail: claus.koelblinger@bhs.at [KH Barmherzige Schwestern Ried, Department of Radiology (Austria); Strauss, Sandra, E-mail: s.strauss@ucl.ac.uk [UCL and UCLH, Department of Medical Oncology (United Kingdom); Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Department of Radiology (United Kingdom)

    2013-05-14T23:59:59.000Z

    PurposeResection is the mainstay of management in patients with sarcoma lung metastases, but there is a limit to how many resections can be performed. Some patients with inoperable disease have small-volume lung metastases that are amenable to thermal ablation. We report our results after radiofrequency ablation (RFA).MethodsThis is a retrospective study of patients treated from 2007 to 2012 in whom the intention was to treat all sites of disease and who had a minimum CT follow-up of 4 months. Treatment was performed under general anesthesia/conscious sedation using cool-tip RFA. Follow-up CT scans were analyzed for local control. Primary tumor type, location, grade, disease-free interval, prior resection/chemotherapy, number and size of lung tumors, uni- or bilateral disease, complications, and overall and progression-free survival were recorded.ResultsTwenty-two patients [15 women; median age 48 (range 10–78) years] with 55 lung metastases were treated in 30 sessions. Mean and median tumor size and initial number were 0.9 cm and 0.7 (range 0.5–2) cm, and 2.5 and 1 (1–7) respectively. Median CT and clinical follow-up were 12 (4–54) and 20 (8–63) months, respectively. Primary local control rate was 52 of 55 (95 %). There were 2 of 30 (6.6 %) Common Terminology Criteria grade 3 complications with no long-term sequelae. Mean (median not reached) and 2- and 3-year overall survival were 51 months, and 94 and 85 %. Median and 1- and 2-year progression-free survival were 12 months, and 53 and 23 %. Prior disease-free interval was the only significant factor to affect overall survival.ConclusionRFA is a safe and effective treatment for patients with small-volume sarcoma metastases.

  7. Stereotactic Radiofrequency Ablation of Unresectable Intrahepatic Cholangiocarcinomas: A Retrospective Study

    SciTech Connect (OSTI)

    Haidu, Marion, E-mail: marion.haidu@i-med.ac.at [Medical University Innsbruck, Clinic of Radiology, Department of Microinvasive Therapy (SIP) (Austria); Dobrozemsky, Georg, E-mail: georg.dobroszemsky@i-med.ac.at [Medical University Innsbruck, Department of Nuclear Medicine (Austria); Schullian, Peter, E-mail: peter.schullian@i-med.ac.at; Widmann, Gerlig, E-mail: gerlig.widmann@i-med.ac.at [Medical University Innsbruck, Clinic of Radiology, Department of Microinvasive Therapy (SIP) (Austria); Klaus, Alexander, E-mail: alexander.klaus@bhs.at; Weiss, Helmut, E-mail: helmut.weiss@bbsalz.at; Margreiter, Raimund, E-mail: raimund.margreiter@i-med.ac.at [Medical University Innsbruck, Department of Surgery (Austria); Bale, Reto, E-mail: reto.bale@i-med.ac.at [Medical University Innsbruck, Clinic of Radiology, Department of Microinvasive Therapy (SIP) (Austria)

    2012-10-15T23:59:59.000Z

    Purpose: To evaluate treatment effects, complications, and outcome of percutaneous stereotactic radiofrequency ablation (SRFA) of intrahepatic cholangiocarcinoma (ICC). Patients and Methods: Eleven consecutive patients (nine men and two women) with a total of 36 inoperable ICCs (18 initial lesions, 16 lesions newly detected during follow-up, and two local recurrences) underwent SRFA between December 2004 and June 2010. Two different radiofrequency ablation (RFA) devices with internally cooled electrodes were used. Tumor diameters ranged from 0.5 to 10 cm (median 3.0 cm). A total of 23 SRFA sessions were performed. The efficacy of SRFA was evaluated by contrast-enhanced computed tomography or magnetic resonance imaging 1 month after treatment and then every 3 months. Results: Primary technical effectiveness rate was 92%. Further follow-up every 3 months revealed three local recurrences (8%), two of which were successfully retreated, resulting in a secondary technical effectiveness rate of 98%. After a total of 23 RFA sessions, three major complications occurred (13%) that could be managed interventionally. Mean follow-up time was 35 months (range 12-81 months). One- and 3-year overall survival rates were 91 and 71%, respectively. The median overall survival was 60 months (according to the life table method). Eight (73%) of 11 patients were still alive at the end of follow-up. Conclusion: SRFA is effective in the treatment of unresectable ICC even if the tumor is large and located close to major vessels. SRFA shows a survival benefit compared to other palliative treatment options and may also be considered as the first-line local treatment of ICCs in selected patients.

  8. RESOLUTION OF URANIUM ISOTOPES WITH KINETIC PHOSPHORESCENCE ANALYSIS

    SciTech Connect (OSTI)

    Miley, Sarah M.; Hylden, Anne T.; Friese, Judah I.

    2013-04-01T23:59:59.000Z

    This study was conducted to test the ability of the Chemchek™ Kinetic Phosphorescence Analyzer Model KPA-11 with an auto-sampler to resolve the difference in phosphorescent decay rates of several different uranium isotopes, and therefore identify the uranium isotope ratios present in a sample. Kinetic phosphorescence analysis (KPA) is a technique that provides rapid, accurate, and precise determination of uranium concentration in aqueous solutions. Utilizing a pulsed-laser source to excite an aqueous solution of uranium, this technique measures the phosphorescent emission intensity over time to determine the phosphorescence decay profile. The phosphorescence intensity at the onset of decay is proportional to the uranium concentration in the sample. Calibration with uranium standards results in the accurate determination of actual concentration of the sample. Different isotopes of uranium, however, have unique properties which should result in different phosphorescence decay rates seen via KPA. Results show that a KPA is capable of resolving uranium isotopes.

  9. Kinetics and mechanisms of reactions involving small aromatic reactive intermediates

    SciTech Connect (OSTI)

    Lin, M.C. [Emory Univ., Atlanta, GA (United States)

    1993-12-01T23:59:59.000Z

    Small aromatic radicals such as C{sub 6}H{sub 5}, C{sub 6}H{sub 5}O and C{sub 6}H{sub 4} are key prototype species of their homologs. C{sub 6}H{sub 5} and its oxidation product, C{sub 6}H{sub 5}O are believed to be important intermediates which play a pivotal role in hydrocarbon combustion, particularly with regard to soot formation. Despite their fundamental importance, experimental data on the reaction mechanisms and reactivities of these species are very limited. For C{sub 6}H{sub 5}, most kinetic data except its reactions with NO and NO{sub 2}, were obtained by relative rate measurements. For C{sub 6}H{sub 5}O, the authors have earlier measured its fragmentation reaction producing C{sub 5}H{sub 5} + CO in shock waves. For C{sub 6}H{sub 4}, the only rate constant measured in the gas phase is its recombination rate at room temperature. The authors have proposed to investigate systematically the kinetics and mechanisms of this important class of molecules using two parallel laser diagnostic techniques--laser resonance absorption (LRA) and resonance enhanced multiphoton ionization mass spectrometry (REMPI/MS). In the past two years, study has been focused on the development of a new multipass adsorption technique--the {open_quotes}cavity-ring-down{close_quotes} technique for kinetic applications. The preliminary results of this study appear to be quite good and the sensitivity of the technique is at least comparable to that of the laser-induced fluorescence method.

  10. Nonlinear effects in kinetic resolutions

    E-Print Network [OSTI]

    Johnson, Derrell W.

    1999-01-01T23:59:59.000Z

    KTRIC AMPLIFICATION IN THE JACOBSEN HYDROLYTIC KINET RESOLUTION OF RACEMIC EPOXIDES 20 Applicability of Homocompetitive Reaction Kinetics to the Jacobsen HKR Effect of Catalyst EE and Choice of Epoxide on Amplification in the Jacobsen HKR.... . . . . . . . . . . . . . . . . . Effect of Temperature on Amplification and Reaction Rate in the Jacobsen HKR . Effect of Low EE Catalyst Generation on Amplification in the Jacobsen HKR. . . . 21 21 25 26 27 30 31 TABLE OF CONTENTS (Continued) CHAPTER Page V AS...

  11. Kinetic models of opinion formation

    E-Print Network [OSTI]

    G. Toscani

    2006-05-17T23:59:59.000Z

    We introduce and discuss certain kinetic models of (continuous) opinion formation involving both exchange of opinion between individual agents and diffusion of information. We show conditions which ensure that the kinetic model reaches non trivial stationary states in case of lack of diffusion in correspondence of some opinion point. Analytical results are then obtained by considering a suitable asymptotic limit of the model yielding a Fokker-Planck equation for the distribution of opinion among individuals.

  12. Ultrafast imaging interferometry at femtosecond-laser-excited surfaces

    SciTech Connect (OSTI)

    Temnov, Vasily V.; Sokolowski-Tinten, Klaus; Zhou Ping; Linde, Dietrich von der [Experimentelle Physik IIb, Universitaet Dortmund, 44221 Dortmund (Germany); Institut fuer Experimentelle Physik, Universitaet Duisburg-Essen, 45117 Essen (Germany)

    2006-09-15T23:59:59.000Z

    A simple and robust setup for femtosecond time-resolved imaging interferometry of surfaces is described. The apparatus is capable of measuring both very small phase shifts ({approx}3x10{sup -2} rad) and amplitude changes ({approx}1%) with micrometer spatial resolution ({approx}1 {mu}m). Interferograms are processed using a 2D-Fourier transform algorithm. We discuss the image formation and the physical interpretation of the measured interferograms. The technique is applied to measure transient changes of a GaAs surface irradiated with intense femtosecond laser pulses with fluences near the ablation threshold.

  13. Measurement of thermally ablated lesions in sonoelastographic images using level set methods

    E-Print Network [OSTI]

    Parker, Kevin J.

    such as radiofrequency ablation (RFA) and high intensity focused ultrasound (HIFU) have attracted the interest as hypo-attenuating regions. However, it also presents disadvantages such as ionizing radiation exposure

  14. Bulk ablation of soft tissue with intense ultrasound: Modeling and experiments

    E-Print Network [OSTI]

    Mast, T. Douglas

    , the thermal de- struction of large tissue volumes is most commonly per- formed using radiofrequency RF ablation electromagnetic radiation in the 400­700 kHz range .3,4 Intense ultrasound treatment, first

  15. Microstructural Evolution During Laser Resolidification of Fe-25 Atom Percent Ge Alloy

    E-Print Network [OSTI]

    Srivastava, Kumar Vaibhav

    selection is discussed using competitive growth kinetics. I. INTRODUCTION TECHNIQUES of rapidly melting the process of laser resolidification. Third, the inti- mate contact of the surface-melted layerMicrostructural Evolution During Laser Resolidification of Fe-25 Atom Percent Ge Alloy KRISHANU

  16. COMPI,,PTATIONALMODEL OF SURFACE ABLATION FROM TOKAMAK DISRUPTIONS

    E-Print Network [OSTI]

    Harilal, S. S.

    , with U I = 9.1 MJ/m 2 heat load over a 100 Its duration. more typical of thermal disruptions and plasma to low kinetic energy particles (_ 100 eV). physics calculations which have little bearing on the final. Details of our atomic physics with plasma gun erosion tests on several metal targets, calculation compare

  17. FREE ELECTRON LASERS

    E-Print Network [OSTI]

    Colson, W.B.

    2008-01-01T23:59:59.000Z

    1984). Colson, W. B. , "Free electron laser theory," Ph.D.aspects of the free electron laser," Laser Handbook i,Quant. Elect. Bendor Free Electron Laser Conference, Journal

  18. CT imaging during microwave ablation: Analysis of spatial and temporal tissue contraction

    SciTech Connect (OSTI)

    Liu, Dong; Brace, Christopher L., E-mail: clbrace@wisc.edu [Departments of Radiology and Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53705 (United States)

    2014-11-01T23:59:59.000Z

    Purpose: To analyze the spatial distribution and temporal development of liver tissue contraction during high-temperature ablation by using intraprocedural computed tomography (CT) imaging. Methods: A total of 46 aluminum fiducial markers were positioned in a 60 × 45 mm grid, in a single plane, around a microwave ablation antenna in each of six ex vivo bovine liver samples. Ablations were performed for 10 min at 100 W. CT data of the liver sample were acquired every 30 s during ablation. Fiducial motion between acquisitions was tracked in postprocessing and used to calculate measures of tissue contraction and contraction rates. The spatial distribution and temporal evolution of contraction were analyzed. Results: Fiducial displacement indicated that the zone measured postablation was 8.2 ± 1.8 mm (?20%) smaller in the radial direction and 7.1 ± 1.0 mm (?10%) shorter in the longitudinal direction than the preablation tissue dimension. Therefore, the total ablation volume was reduced from its preablation value by approximately 45%. Very little longitudinal contraction was noted in the distal portion of the ablation zone. Central tissues contracted more than 60%, which was near an estimated limit of ?70% based on initial water content. More peripheral tissues contracted only 15% in any direction. Contraction rates peaked during the first 60 s of heating with a roughly exponential decay over time. Conclusions: Ablation zones measured posttreatment are significantly smaller than the pretreatment tissue dimensions. Tissue contraction is spatially dependent, with the greatest effect occurring in the central ablation zone. Contraction rate peaks early and decays over time.

  19. Optimization of Direct Current-Enhanced Radiofrequency Ablation: An Ex Vivo Study

    SciTech Connect (OSTI)

    Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp; Isfort, Peter; Bruners, Philipp; Penzkofer, Tobias [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen (Germany); Kichikawa, Kimihiko [Nara Medical University, Department of Radiology (Japan); Schmitz-Rode, Thomas; Mahnken, Andreas H. [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen (Germany)

    2010-10-15T23:59:59.000Z

    The purpose of this study was to investigate the optimal setting for radiofrequency (RF) ablation combined with direct electrical current (DC) ablation in ex vivo bovine liver. An electrical circuit combining a commercially available RF ablation system with DC was developed. The negative electrode of a rectifier that provides DC was connected to a 3-cm multitined expandable RF probe. A 100-mH inductor was used to prevent electrical leakage from the RF generator. DC was applied for 15 min and followed by RF ablation in freshly excised bovine livers. Electric current was measured by an ammeter. Coagulation volume, ablation duration, and mean amperage were assessed for various DC voltages (no DC, 2.2, 4.5, and 9.0 V) and different RF ablation protocols (stepwise increase from 40 to 80 W, 40 W fixed, and 80 W fixed). Results were compared using Kruskal-Wallis and Mann-Whitney U test. Applying DC with 4.5 or 9.0 V, in combination with 40 W fixed or a stepwise increase of RF energy, resulted in significantly increased zone of ablation size compared with 2.2 V or no DC (P = 0.009). At 4.5 V DC, the stepwise increase of RF energy resulted in the same necrosis size as a 40 W fixed protocol (26.6 {+-} 3.9 vs. 26.5 {+-} 4.0 ml), but ablation duration was significantly decreased (296 {+-} 85 s vs. 423 {+-} 104 s; P = 0.028). Mean amperage was significantly lower at 4.5 V compared with 9.0 V (P = 0.028). Combining a stepwise increase of RF energy with a DC voltage of 4.5 V is most appropriate to increase coagulation volume and to minimize procedure time.

  20. Advances in petascale kinetic plasma simulation with VPIC and Roadrunner

    SciTech Connect (OSTI)

    Bowers, Kevin J [Los Alamos National Laboratory; Albright, Brian J [Los Alamos National Laboratory; Yin, Lin [Los Alamos National Laboratory; Daughton, William S [Los Alamos National Laboratory; Roytershteyn, Vadim [Los Alamos National Laboratory; Kwan, Thomas J T [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    VPIC, a first-principles 3d electromagnetic charge-conserving relativistic kinetic particle-in-cell (PIC) code, was recently adapted to run on Los Alamos's Roadrunner, the first supercomputer to break a petaflop (10{sup 15} floating point operations per second) in the TOP500 supercomputer performance rankings. They give a brief overview of the modeling capabilities and optimization techniques used in VPIC and the computational characteristics of petascale supercomputers like Roadrunner. They then discuss three applications enabled by VPIC's unprecedented performance on Roadrunner: modeling laser plasma interaction in upcoming inertial confinement fusion experiments at the National Ignition Facility (NIF), modeling short pulse laser GeV ion acceleration and modeling reconnection in magnetic confinement fusion experiments.

  1. Systems and methods for laser assisted sample transfer to solution for chemical analysis

    DOE Patents [OSTI]

    Van Berkel, Gary J; Kertesz, Vilmos; Ovchinnikova, Olga S

    2013-08-27T23:59:59.000Z

    Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

  2. Systems and methods for laser assisted sample transfer to solution for chemical analysis

    SciTech Connect (OSTI)

    Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

    2014-06-03T23:59:59.000Z

    Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

  3. A laser-based solution to industrial decontamination problems

    SciTech Connect (OSTI)

    Edelson, M.C.; Pang, Ho-ming [Ames Lab., IA (United States); Ferguson, R.L. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

    1995-12-31T23:59:59.000Z

    The ability of lasers to deposit significant amounts of energy on surfaces located at large distances from the laser can be exploited to solve very difficult industrial problems. The Ames Laboratory has been working in partnership with Lockheed Martin Idaho Technologies (LMIT) to apply laser technologies to the decontamination of radioactively contaminated surfaces located in hostile environments. Many such applications exist within former USDOE and nuclear industry facilities. As opposed to laser coating removal systems, which are designed to ``strip`` relatively soft coatings from a substrate without damage to the substrate, the system being developed by Ames - LMIT is designed to remove contaminants that are embedded within the metal surface itself. The system generates irradiance levels sufficient to remove microns of metal from a surface and an off-gas system that prevents the redeposition of materials removed from the surface. Process control is assisted by monitoring the laser-generated plasma produced during laser surface ablation. Results achieved using this apparatus for various metal types will be presented along with a discussion of other potential industrial applications.

  4. Promethium-doped phosphate glass laser at 933 and 1098 nm

    SciTech Connect (OSTI)

    Krupke, W.F.; Shinn, M.D.; Kirchoff, T.A.; Finch, C.B.; Boatner, L.A.

    1987-12-28T23:59:59.000Z

    A promethium (Pm/sup 3 +/) laser has been demonstrated for the first time. Trivalent promethium 147 doped into a lead-indium-phosphate glass etalon was used to produce room-temperature four-level laser emission at wavelengths of 933 and 1098 nm. Spectroscopic and kinetic measurements have shown that Pm/sup 3 +/ is similar to Nd/sup 3 +/ as a laser active ion.

  5. Amplified short-wavelength light scattered by relativistic electrons in the laser-induced optical lattice

    E-Print Network [OSTI]

    Andriyash, I A; Malka, V; d'Humières, E; Balcou, Ph

    2014-01-01T23:59:59.000Z

    The scheme of the XUV/X-ray free electron laser based on the optical undulator created by two overlapped transverse laser beams is analyzed. A kinetic theoretical description and an ad hoc numerical model are developed to account for the finite energy spread, angular divergence and the spectral properties of the electron beam in the optical lattice. The theoretical findings are compared to the results of the one- and three-dimensional numerical modeling with the spectral free electron laser code PLARES.

  6. Laser barometer

    DOE Patents [OSTI]

    Abercrombie, Kevin R. (Westminster, CO); Shiels, David (Thornton, CO); Rash, Tim (Aurora, CO)

    2001-02-06T23:59:59.000Z

    A pressure measuring instrument that utilizes the change of the refractive index of a gas as a function of pressure and the coherent nature of a laser light to determine the barometric pressure within an environment. As the gas pressure in a closed environment varies, the index of refraction of the gas changes. The amount of change is a function of the gas pressure. By illuminating the gas with a laser light source, causing the wavelength of the light to change, pressure can be quantified by measuring the shift in fringes (alternating light and dark bands produced when coherent light is mixed) in an interferometer.

  7. SLAM: a sodium-limestone concrete ablation model

    SciTech Connect (OSTI)

    Suo-Anttila, A.J.

    1983-12-01T23:59:59.000Z

    SLAM is a three-region model, containing a pool (sodium and reaction debris) region, a dry (boundary layer and dehydrated concrete) region, and a wet (hydrated concrete) region. The model includes a solution to the mass, momentum, and energy equations in each region. A chemical kinetics model is included to provide heat sources due to chemical reactions between the sodium and the concrete. Both isolated model as well as integrated whole code evaluations have been made with good results. The chemical kinetics and water migration models were evaluated separately, with good results. Several small and large-scale sodium limestone concrete experiments were simulated with reasonable agreement between SLAM and the experimental results. The SLAM code was applied to investigate the effects of mixing, pool temperature, pool depth and fluidization. All these phenomena were found to be of significance in the predicted response of the sodium concrete interaction. Pool fluidization is predicted to be the most important variable in large scale interactions.

  8. Rapid Proton Transfer Mediated by a Strong Laser Field

    SciTech Connect (OSTI)

    Markevitch, Alexei N.; Levis, Robert J. [Department of Chemistry, Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122 (United States); Romanov, Dmitri A. [Department of Physics, Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122 (United States); Smith, Stanley M. [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)

    2006-04-28T23:59:59.000Z

    Kinetic energy distributions of H{sup +} ejected from a polyatomic molecule, anthraquinone, subjected to 60 fs, 800 nm laser pulses of intensity between 0.2 and 4.0x10{sup 14} W{center_dot}cm{sup -2}, reveal field-driven restructuring of the molecule prior to Coulomb explosion. Calculations demonstrate fast intramolecular proton migration into a field-dressed metastable potential energy minimum. The proton migration occurs in the direction perpendicular to the polarization of the laser field. Rapid field-mediated isomerization is an important new phenomenon in coupling of polyatomic molecules with intense lasers.

  9. Percutaneous Radiofrequency Lung Ablation Combined with Transbronchial Saline Injection: An Experimental Study in Swine

    SciTech Connect (OSTI)

    Kawai, T., E-mail: t-kawai@hosp.yoka.hyogo.jp; Kaminou, T., E-mail: kaminout@grape.med.tottori-u.ac.jp; Sugiura, K.; Hashimoto, M.; Ohuchi, Y.; Adachi, A. [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine (Japan); Fujioka, S.; Ito, H. [Tottori University, Division of Organ Pathology, Department of Microbiology and Pathology, Faculty of Medicine (Japan); Nakamura, K. [Hakuai Hospital, Department of Radiology (Japan); Ihaya, T. [Sanin Rosai Hospital, Department of Radiology (Japan); Ogawa, T. [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine (Japan)

    2010-02-15T23:59:59.000Z

    To evaluate the efficacy of radiofrequency lung ablation with transbronchial saline injection. The bilateral lungs of eight living swine were used. A 13-gauge bone biopsy needle was inserted percutaneously into the lung, and 1 ml of muscle paste was injected to create a tumor mimic. In total, 21 nodules were ablated. In the saline injection group (group A), radiofrequency ablation (RFA) was performed for 11 nodules after transbronchial saline injection under balloon occlusion with a 2-cm active single internally cooled electrode. In the control group (group B), conventional RFA was performed for 10 nodules as a control. The infused saline liquid showed a wedge-shaped and homogeneous distribution surrounding a tumor mimic. All 21 RFAs were successfully completed. The total ablation time was significantly longer (13.4 {+-} 2.8 min vs. 8.9 {+-} 3.5 min; P = 0.0061) and the tissue impedance was significantly lower in group A compared with group B (73.1 {+-} 8.8 {Omega} vs. 100.6 {+-} 16.6 {Omega}; P = 0.0002). The temperature of the ablated area was not significantly different (69.4 {+-} 9.1{sup o}C vs. 66.0 {+-} 7.9{sup o}C; P = 0.4038). There was no significant difference of tumor mimic volume (769 {+-} 343 mm{sup 3} vs. 625 {+-} 191 mm{sup 3}; P = 0.2783). The volume of the coagulated area was significantly larger in group A than in group B (3886 {+-} 1247 mm{sup 3} vs. 2375 {+-} 1395 mm{sup 3}; P = 0.0221). Percutaneous radiofrequency lung ablation combined with transbronchial saline injection can create an extended area of ablation.

  10. Lung Radiofrequency Ablation: In Vivo Experimental Study with Low-Perfusion-Rate Multitined Electrodes

    SciTech Connect (OSTI)

    Crocetti, Laura, E-mail: l.crocetti@med.unipi.it; Lencioni, Riccardo; Bozzi, Elena [University of Pisa, Division of Diagnostic and Interventional Radiology, Department of Oncology, Transplant and Advanced Technologies in Medicine (Italy); Sbrana, Alberto [University of Pisa (Italy); Bartolozzi, Carlo [University of Pisa, Division of Diagnostic and Interventional Radiology, Department of Oncology, Transplant and Advanced Technologies in Medicine (Italy)

    2008-05-15T23:59:59.000Z

    The purpose of this study was to investigate the feasibility and safety of lung radiofrequency (RF) ablation by using low-perfusion-rate, expandable, multitined electrodes in an in vivo animal model. Ten New Zealand White rabbits underwent RF ablation using low-perfusion-rate, expandable, multitined electrodes (Starburst Talon; RITA Medical Systems, Mountain View, CA) and a 200-W RF generator. The electrode was positioned under fluoroscopy guidance and a single percutaneous RF ablation was performed. Saline perfusate was doped with nonionic iodinated contrast agent to render it visible on computed tomography (CT). The pump infused the saline doped with contrast agent into the lateral tines at a rate of 0.1ml/min. The planned ablation was of 3 min, with the hooks deployed to 2 cm at a target temperature of 105{sup o}C. An immediate posttreatment CT scan documented the distribution of the doped saline and the presence of immediate complications. The animals were monitored for delayed complications and sacrificed within 72 h (n = 4), 2 weeks (n = 3), or 4 weeks (n = 3). Assessment of ablation zone and adjacent structures was done at autopsy. Major complications consisted of pneumothorax requiring drainage (n = 2) and skin burn (n = 1). Immediately after the procedure the area of ablation was depicted at CT as a round, well-demarcated area, homogeneously opacified by iodinated contrast medium (mean size, 2.3 {+-} 0.8 cm). The presence of a sharply demarcated area of coagulation necrosis (mean size, 2.1 {+-} 0.4 cm) without severe damage to adjacent structures was confirmed at autopsy. In one case, euthanized at 4 weeks, in whom pneumothorax and pleural effusion were depicted, pleural fibrinous adhesions were demonstrated at autopsy. In conclusion, lung RF ablation performed in an in vivo animal model using low-perfusion-rate, expandable, multitined electrodes is feasible and safe. No severe damage to adjacent structures was demonstrated.

  11. From ripples to spikes: a hydro-dynamical physical mechanism to interpret femtosecond laser induced self-assembled structures

    E-Print Network [OSTI]

    Tsibidis, George D; Stratakis, Emmanuel

    2015-01-01T23:59:59.000Z

    Materials irradiated with multiple femtosecond laser pulses in sub-ablation conditions are observed to develop various types of self-assembled morphologies that range from nano-ripples to periodic micro-grooves and quasi-periodic micro-spikes. Here, we present a physical scenario that couples electrodynamics, describing surface plasmon excitation, with hydrodynamics, describing Marangoni convection, to elucidate this important sub-ablation regime of light matter interaction in which matter is being modified, however, the underlying process is not yet fully understood. The proposed physical mechanism could be generally applicable to practically any conductive material structured by ultrashort laser pulses, therefore it can be useful for the interpretation of further critical aspects of light matter interaction.

  12. Chemical kinetics and combustion modeling

    SciTech Connect (OSTI)

    Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01T23:59:59.000Z

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  13. Desorption Kinetics of Methanol, Ethanol, and Water from Graphene...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Desorption Kinetics of Methanol, Ethanol, and Water from Graphene. Desorption Kinetics of Methanol, Ethanol, and Water from Graphene. Abstract: The desorption kinetics of methanol,...

  14. System and method of infrared matrix-assisted laser desorption/ionization mass spectrometry in polyacrylamide gels

    DOE Patents [OSTI]

    Haglund Jr., Richard F.; Ermer, David R.; Baltz-Knorr, Michelle Lee

    2004-11-30T23:59:59.000Z

    A system and method for desorption and ionization of analytes in an ablation medium. In one embodiment, the method includes the steps of preparing a sample having analytes in a medium including at least one component, freezing the sample at a sufficiently low temperature so that at least part of the sample has a phase transition, and irradiating the frozen sample with short-pulse radiation to cause medium ablation and desorption and ionization of the analytes. The method further includes the steps of selecting a resonant vibrational mode of at least one component of the medium and selecting an energy source tuned to emit radiation substantially at the wavelength of the selected resonant vibrational mode. The medium is an electrophoresis medium having polyacrylamide. In one embodiment, the energy source is a laser, where the laser can be a free electron laser tunable to generate short-pulse radiation. Alternatively, the laser can be a solid state laser tunable to generate short-pulse radiation. The laser can emit light at various ranges of wavelength.

  15. Feedback-controlled laser fabrication of micromirror substrates

    E-Print Network [OSTI]

    Benjamin Petrak; Kumarasiri Konthasinghe; Sonia Perez; Andreas Muller

    2012-06-11T23:59:59.000Z

    Short (40-200 microseconds) single focused CO2 laser pulses of energy of about 100 microJ were used to fabricate high quality concave micromirror templates on silica and fluoride glass. The ablated features have diameters of 20-100 microns and average root-mean-square (RMS) surface microroughness near their center of less than 0.2 nm. Temporally monitoring the fabrication process revealed that it proceeds on a time scale shorter than the laser pulse duration. We implement a fast feedback control loop (20 kHz bandwidth) based on the light emitted by the sample that ensures an RMS size dispersion of less than 5 percent in arrays on chips or in individually fabricated features on an optical fiber tip, a significant improvement over previous approaches using longer pulses and open loop operation.

  16. Tailoring the air plasma with a double laser pulse

    SciTech Connect (OSTI)

    Shneider, M. N.; Miles, R. B. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263 (United States); Zheltikov, A. M. [Physics Department, International Laser Center, M. V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843-4242 (United States)

    2011-06-15T23:59:59.000Z

    We present a comprehensive model of plasma dynamics that enables a detailed understanding of the ways the air plasma induced in the atmosphere in the wake of a laser-induced filament can be controlled by an additional laser pulse. Our model self-consistently integrates plasma-kinetic, Navier-Stokes, electron heat conduction, and electron-vibration energy transfer equations, serving to reveal laser-plasma interaction regimes where the plasma lifetime can be substantially increased through an efficient control over plasma temperature, as well as suppression of attachment and recombination processes. The model is used to quantify the limitations on the length of uniform laser-filament heating due to the self-defocusing of laser radiation by the radial profile of electron density. The envisaged applications include sustaining plasma guides for long-distance transmission of microwaves, standoff detection of impurities and potentially hazardous agents, as well as lightning control and protection.

  17. Tunable, diode side-pumped Er: YAG laser

    DOE Patents [OSTI]

    Hamilton, Charles E. (Bellevue, WA); Furu, Laurence H. (Modesto, CA)

    1997-01-01T23:59:59.000Z

    A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 .mu.m, and is tunable over a 6 nm range near about 2.936 .mu.m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 .mu.m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 .mu.m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems.

  18. Laser thermoelastic generation in metals above the melt threshold

    SciTech Connect (OSTI)

    Every, A. G. [School of Physics, University of the Witwatersrand, PO Wits 2050 (South Africa)] [School of Physics, University of the Witwatersrand, PO Wits 2050 (South Africa); Utegulov, Z. N. [Department of Physics, School of Science and Technology, Nazarbayev University, Astana 010000 (Kazakhstan)] [Department of Physics, School of Science and Technology, Nazarbayev University, Astana 010000 (Kazakhstan); Veres, I. A. [RECENDT Research Center for Non-Destructive Testing GmbH, A-4040 Linz (Austria)] [RECENDT Research Center for Non-Destructive Testing GmbH, A-4040 Linz (Austria)

    2013-11-28T23:59:59.000Z

    An approach is presented for calculating thermoelastic generation of ultrasound in a metal plate exposed to nanosecond pulsed laser heating, sufficient to cause melting but not ablation. Detailed consideration is given to the spatial and temporal profiles of the laser pulse, penetration of the laser beam into the sample, the appearance and subsequent growth and then contraction of the melt pool, and the time dependent thermal conduction in the melt and surrounding solid throughout. The excitation of the ultrasound takes place during and shortly after the laser pulse and occurs predominantly within the thermal diffusion length of a micron or so beneath the surface. It is shown how, because of this, the output of the thermal simulations can be expressed as axially symmetric transient radial and normal surface force distributions. The epicentral displacement response to these force distributions is obtained by two methods, the one based on the elastodynamic Green's functions for plate geometry determined by the Cagniard generalized ray method and the other using a finite element numerical method. The two approaches are in very close agreement. Numerical simulations are reported on the epicentral displacement response of a 3.12 mm thick tungsten plate irradiated with a 4 ns pulsed laser beam with Gaussian spatial profile, at intensities below and above the melt threshold.

  19. Tunable, diode side-pumped Er:YAG laser

    DOE Patents [OSTI]

    Hamilton, C.E.; Furu, L.H.

    1997-04-22T23:59:59.000Z

    A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 {micro}m, and is tunable over a 6 nm range near about 2.936 {micro}m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 {micro}m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 {micro}m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems. 4 figs.

  20. Improving alternative fuel utilization: detailed kinetic combustion...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Improving alternative fuel utilization: detailed kinetic combustion modeling & experimental testing Salvador Aceves, Daniel Flowers, Bill Pitz, Charlie Westbrook, Emma Silke,...

  1. Kinetic Modeling and Thermodynamic Closure Approximation of ...

    E-Print Network [OSTI]

    2007-10-03T23:59:59.000Z

    Oct 5, 2007 ... Kinetic Modeling and Thermodynamic Closure. Approximation of Liquid Crystal Polymers. Haijun Yu. Program in Applied and Computational ...

  2. Single-Session Radiofrequency Ablation of Bilateral Lung Metastases

    SciTech Connect (OSTI)

    Palussiere, Jean, E-mail: palussiere@bergonie.org; Gomez, Fernando; Cannella, Matthieu; Ferron, Stephane; Descat, Edouard [Institut Bergonie, Department of Radiology, Regional Cancer Centre (France); Fonck, Marianne [Institut Bergonie, Department of Digestive Oncology (France); Brouste, Veronique [Institut Bergonie, Clinical and Epidemiological Research Unit (France); Avril, Antoine [Institut Bergonie, Department of Surgery (France)

    2012-08-15T23:59:59.000Z

    Purpose: This retrospective study examined the feasibility and efficacy of bilateral lung radiofrequency ablation (RFA) performed in a single session. Methods: From 2002-2009, patients with bilateral lung metastases were treated by RFA, where possible in a single session under general anesthesia with CT guidance. The second lung was punctured only if no complications occurred after treatment of the first lung. Five lung metastases maximum per patient were treated by RFA and prospectively followed. The primary endpoint was the evaluation of acute and delayed complications. Secondary endpoints were calculation of hospitalization duration, local efficacy, median survival, and median time to tumor progression. Local efficacy was evaluated on CT or positron emission tomography (PET) CT. Results: Sixty-seven patients were treated for bilateral lung metastases with RFA (mean age, 62 years). Single-session treatment was not possible in 40 due to severe pneumothoraces (n = 24), bilateral pleural contact (n = 14), and operational exclusions (n = 2). Twenty-seven (41%) received single-session RFA of lesions in both lungs for 66 metastases overall. Fourteen unilateral and four bilateral pneumothoraces occurred (18 overall, 66.7%). Unilateral (n = 13) and bilateral (n = 2) chest tube drainage was required. Median hospitalization was 3 (range, 2-8) days. Median survival was 26 months (95% confidence interval (CI), 19-33). Four recurrences on RFA sites were observed (4 patients). Median time to tumor progression was 9.5 months (95% CI, 4.2-23.5). Conclusions: Although performing single-session bilateral lung RFA is not always possible due to pneumothoraces after RFA of first lung, when it is performed, this technique is safe and effective.

  3. "Thermal History of the Bandelier Magmatic System: Evidence for Magma Recharge as Revealed by Cathodoluminescence and Titanium Geothermometry"

    E-Print Network [OSTI]

    ........................................................................................p. 5 · Sample Collection · Sample Preparation · Cathodoluminescence · Laser Ablation Inductively

  4. Real-time magnetic resonance imagingguided radiofrequency atrial ablation and visualization of lesion formation at 3 Tesla

    E-Print Network [OSTI]

    Utah, University of

    of lesion formation at 3 Tesla Gaston R. Vergara, MD,* Sathya Vijayakumar, MS,* Eugene G. Kholmovski, Ph. In this study, we report a novel 3-Tesla RT -RI based porcine RF ablation model and visuali- zation of lesion-Tesla RT MRI-based catheter ablation and lesion visualization system. METHODS RF energy was delivered

  5. Development of a precise size-controllable pellet injector for the detailed studies of ablation phenomena and mechanism

    E-Print Network [OSTI]

    Boyer, Edmond

    Development of a precise size-controllable pellet injector for the detailed studies of ablation, pellet injection experiments have been actively carried out in many toroidal devices in the sense. In order to have a common measure of pellet ablation, the regression study has been performed

  6. Precision Micron Hole Drilling using a Frequency Doubled, Diode Pumped Solid State Laser

    SciTech Connect (OSTI)

    Friedman, H W; Pierce, E L

    2004-04-21T23:59:59.000Z

    This work represents the second phase of a program to demonstrate precision laser drilling with minimal Heat Affected Zone. The technique uses a Diode Pumped Solid State Laser with two wavelengths and two modes of operation. The fundamental mode of the DPSSL at 1.06 microns is used to drill a hole with a diameter of a fraction of a millimeter diameter in a millimeter thick substrate quickly, but with low precision. This hole is then machined to precision dimensions using the second harmonic of the DPSSL Laser at 532 nm using a trepanning technique. Both lasers operate in the ablative mode with peak powers at or above a giga-watt per square centimeter and pulse durations in the 80 - 100 ns range. Under these conditions, the thermal diffusion distance is of the order of a micron or less and that fact coupled with the ablative nature of the process results in little or no HAZ (heat affected zone). With no HAZ, there isn't any change in the crystalline structure surrounding the hole and the strength of the substrate is maintained. Applications for these precision holes include cooling passages in turbine blades, ports for diesel injectors, suction holes for boundary layer control on wings and holes for dies in precision extrusion processes.

  7. Spontaneous Regression of Multiple Pulmonary Metastases After Radiofrequency Ablation of a Single Metastasis

    SciTech Connect (OSTI)

    Rao, Pramod; Escudier, Bernard; Baere, Thierry de, E-mail: debaere@igr.fr [Institut Gustave Roussy, Department of Interventional Radiology (France)

    2011-04-15T23:59:59.000Z

    We report two cases of spontaneous regression of multiple pulmonary metastases occurring after radiofrequency ablation (RFA) of a single lung metastasis. To the best of our knowledge, these are the first such cases reported. These two patients presented with lung metastases progressive despite treatment with interleukin-2, interferon, or sorafenib but were safely ablated with percutaneous RFA under computed tomography guidance. Percutaneous RFA allowed control of the targeted tumors for >1 year. Distant lung metastases presented an objective response despite the fact that they received no targeted local treatment. Local ablative techniques, such as RFA, induce the release of tumor-degradation product, which is probably responsible for an immunologic reaction that is able to produce a response in distant tumors.

  8. Cholecystokinin-Assisted Hydrodissection of the Gallbladder Fossa during FDG PET/CT-guided Liver Ablation

    SciTech Connect (OSTI)

    Tewari, Sanjit O., E-mail: tewaris@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Petre, Elena N., E-mail: petree@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States); Osborne, Joseph, E-mail: osbornej@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States)] [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Sofocleous, Constantinos T., E-mail: sofoclec@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States)

    2013-12-15T23:59:59.000Z

    A 68-year-old female with colorectal cancer developed a metachronous isolated fluorodeoxyglucose-avid (FDG-avid) segment 5/6 gallbladder fossa hepatic lesion and was referred for percutaneous ablation. Pre-procedure computed tomography (CT) images demonstrated a distended gallbladder abutting the segment 5/6 hepatic metastasis. In order to perform ablation with clear margins and avoid direct puncture and aspiration of the gallbladder, cholecystokinin was administered intravenously to stimulate gallbladder contraction before hydrodissection. Subsequently, the lesion was ablated successfully with sufficient margins, of greater than 1.0 cm, using microwave with ultrasound and FDG PET/CT guidance. The patient tolerated the procedure very well and was discharged home the next day.

  9. Laser machining of explosives

    DOE Patents [OSTI]

    Perry, Michael D. (Livermore, CA); Stuart, Brent C. (Fremont, CA); Banks, Paul S. (Livermore, CA); Myers, Booth R. (Livermore, CA); Sefcik, Joseph A. (Tracy, CA)

    2000-01-01T23:59:59.000Z

    The invention consists of a method for machining (cutting, drilling, sculpting) of explosives (e.g., TNT, TATB, PETN, RDX, etc.). By using pulses of a duration in the range of 5 femtoseconds to 50 picoseconds, extremely precise and rapid machining can be achieved with essentially no heat or shock affected zone. In this method, material is removed by a nonthermal mechanism. A combination of multiphoton and collisional ionization creates a critical density plasma in a time scale much shorter than electron kinetic energy is transferred to the lattice. The resulting plasma is far from thermal equilibrium. The material is in essence converted from its initial solid-state directly into a fully ionized plasma on a time scale too short for thermal equilibrium to be established with the lattice. As a result, there is negligible heat conduction beyond the region removed resulting in negligible thermal stress or shock to the material beyond a few microns from the laser machined surface. Hydrodynamic expansion of the plasma eliminates the need for any ancillary techniques to remove material and produces extremely high quality machined surfaces. There is no detonation or deflagration of the explosive in the process and the material which is removed is rendered inert.

  10. Analysis of laser remote fusion cutting based on a mathematical model

    SciTech Connect (OSTI)

    Matti, R. S. [Department of Engineering Sciences and Mathematics, Luleå University of Technology, S-971 87 Luleå (Sweden); Department of Mechanical Engineering, College of Engineering, University of Mosul, Mosul (Iraq); Ilar, T.; Kaplan, A. F. H. [Department of Engineering Sciences and Mathematics, Luleå University of Technology, S-971 87 Luleå (Sweden)

    2013-12-21T23:59:59.000Z

    Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, laser remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too.

  11. Femtosecond laser-induced periodic surface structure on the Ti-based nanolayered thin films

    SciTech Connect (OSTI)

    Petrovi?, Suzana M.; Gakovi?, B.; Peruško, D. [Institute of Nuclear Science—Vin?a, University of Belgrade, POB 522, 11001 Belgrade (Serbia)] [Institute of Nuclear Science—Vin?a, University of Belgrade, POB 522, 11001 Belgrade (Serbia); Stratakis, E. [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece) [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece); Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete (Greece); Bogdanovi?-Radovi?, I. [Ru?er Boškovi? Institute, P.O. Box 180, 10002 Zagreb (Croatia)] [Ru?er Boškovi? Institute, P.O. Box 180, 10002 Zagreb (Croatia); ?ekada, M. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)] [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Fotakis, C. [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece) [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece); Department of Physics, University of Crete, 714 09 Heraklion, Crete (Greece); Jelenkovi?, B. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)] [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)

    2013-12-21T23:59:59.000Z

    Laser-induced periodic surface structures (LIPSSs) and chemical composition changes of Ti-based nanolayered thin films (Al/Ti, Ni/Ti) after femtosecond (fs) laser pulses action were studied. Irradiation is performed using linearly polarized Ti:Sapphire fs laser pulses of 40 fs pulse duration and 800 nm wavelength. The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed at elevated laser fluences. On the contrary, high spatial frequency LIPSS (HSFL) with uniform period of 155 nm, parallel to the laser light polarization, appeared at low laser fluences, as well as in the wings of the Gaussian laser beam distribution for higher used fluence. LSFL formation was associated with the material ablation process and accompanied by the intense formation of nanoparticles, especially in the Ni/Ti system. The composition changes at the surface of both multilayer systems in the LSFL area indicated the intermixing between layers and the substrate. Concentration and distribution of all constitutive elements in the irradiated area with formed HSFLs were almost unchanged.

  12. BNL | CO2 Laser

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CO2 Laser The ATF is one of the only two facilities worldwide operating picosecond, terawatt-class CO2 lasers. Our laser system consists of a picoseconds pulse-injector based on...

  13. FREE-ELECTRON LASERS

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    Variable-Wiggler Free-Electron-Laser Oscillat.ion. Phys. :_.The Los Alamos Free Electron Laser: Accelerator Perfoemance.First Operation of a Free-Electron Laser. Phys . __ Rev~.

  14. Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon Degradation. Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon Degradation. Abstract: Many...

  15. Challenges and Progress Toward a Commercial Kinetic Hydropower System

    E-Print Network [OSTI]

    Walter, M.Todd

    Challenges and Progress Toward a Commercial Kinetic Hydropower System for its kinetic hydropower devices, and has made precise measurements

  16. Life-Threatening Hematuria Requiring Transcatheter Embolization Following Radiofrequency Ablation of Renal Cell Carcinoma

    SciTech Connect (OSTI)

    Roach, H. [Bristol Royal Infirmary, Department of Radiology (United Kingdom); Whittlestone, T. [Bristol Royal Infirmary, Department of Urology (United Kingdom); Callaway, M.P. [Bristol Royal Infirmary, Department of Radiology (United Kingdom)], E-mail: Mark.Callaway@ubht.swest.nhs.uk

    2006-08-15T23:59:59.000Z

    Radiofrequency ablation is increasingly being acknowledged as a valid treatment for renal cell carcinoma in patients in whom definitive curative resection is deemed either undesirable or unsafe. A number of published series have shown the technique to have encouraging results and relatively low complication rates. In this article, we report a case of delayed life-threatening hematuria requiring transcatheter embolization of a bleeding intrarenal artery in a patient who had undergone imaging-guided radiofrequency ablation of a 3 cm renal cell carcinoma. To our knowledge, such a complication has not been reported previously.

  17. Transcatheter Arterial Embolization for Tumor Seeding in the Chest Wall After Radiofrequency Ablation for Hepatocellular Carcinoma

    SciTech Connect (OSTI)

    Shibata, Toshiya, E-mail: ksj@kuhp.kyoto-u.ac.jp; Shibata, Toyomichi; Maetani, Yoji; Kubo, Takeshi [Kyoto University Graduate School of Medicine, Department of Diagnostic Imaging and Nuclear Medicine (Japan); Nishida, Naoshi [Kyoto University Graduate School of Medicine, Endocrinology (Japan); Itoh, Kyo [Kyoto University Graduate School of Medicine, Department of Diagnostic Imaging and Nuclear Medicine (Japan)

    2006-06-15T23:59:59.000Z

    Tumor seeding in the chest wall was depicted at follow-up CT obtained 9 months after radiofrequency ablation for hepatocellular carcinoma. Transcatheter arterial embolization was successfully performed, injecting emulsion of 10 mg of epirubicin and 1 ml of iodized oil followed by gelatin sponge particles via the microcatheter placed in the right eleventh intercostal artery. The patient died of tumor growth in the liver one year after the embolization, but no progression of the tumor seeding was noted during the follow-up period. We conclude that transcatheter arterial embolization was effective for the control of tumor seeding after radiofrequency ablation for hepatocellular carcinoma.

  18. Combined MRI and Fluoroscopic Guided Radiofrequency Ablation of a Renal Tumor

    SciTech Connect (OSTI)

    Fotiadis, Nikolas I., E-mail: fotiadis.nicholas@gmail.co [Royal London Hospital, Department of Interventional Radiology (United Kingdom); Sabharwal, Tarun [Guy's and St Thomas' Hospital, Interventional Radiology Department (United Kingdom); Gangi, Afshin [University Hospital of Strasbourg, Radiology Department (France); Adam, Andreas [Guy's and St Thomas' Hospital, Interventional Radiology Department (United Kingdom)

    2009-01-15T23:59:59.000Z

    Percutaneous CT- and ultrasound-guided radiofrequency ablation of renal cell carcinoma (RCC) has been shown to have very promising medium-term results. We present a unique case of recurrent RCC after partial nephrectomy in a patient with a single kidney and impaired renal function. This tumor could not be visualized either with CT or with ultrasound. A combination of magnetic resonance imaging and fluoroscopic guidance was used, to the best of our knowledge for the first time, to ablate the tumor with radiofrequency. The patient was cancer-free and off dialysis at 30-month follow up.

  19. Shock-less interactions of ablation streams in tungsten wire array z-pinches

    SciTech Connect (OSTI)

    Swadling, G. F.; Lebedev, S. V.; Hall, G. N.; Suzuki-Vidal, F.; Burdiak, G.; Harvey-Thompson, A. J.; Bland, S. N.; De Grouchy, P.; Khoory, E.; Pickworth, L.; Skidmore, J.; Suttle, L. [The Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)] [The Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)

    2013-06-15T23:59:59.000Z

    Shock-less dynamics were observed during the ablation phase in tungsten wire array experiments carried out on the 1.4 MA, 240 ns MAGPIE generator at Imperial College London. This behaviour contrasts with the shock structures which were seen to dominate in previous experiments on aluminium arrays [Swadling et al., Phys. Plasmas 20, 022705 (2013)]. In this paper, we present experimental results and make comparisons both with calculations of the expected mean free paths for collisions between the ablation streams and with previously published Thomson scattering measurements of the plasma parameters in these arrays [Harvey-Thompson et al., Phys. Plasmas 19, 056303 (2012)].

  20. Laser Safety Management Policy Statement ............................................................................................................1

    E-Print Network [OSTI]

    Davidson, Fordyce A.

    Laser Safety Management Policy Statement...........................................................2 Laser Users.............................................................................................................2 Unit Laser Safety Officer (ULSO

  1. Laser programs highlights 1994

    SciTech Connect (OSTI)

    NONE

    1994-12-31T23:59:59.000Z

    This report provides highlights of the Lawrence Livermore National Laboratories` laser programs. Laser uses and technology assessment and utilization are provided.

  2. BNL | ATF Laser Safety

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    be continuously escorted by someone who has such training: The training consists of an eye exam, BNL general laser safety lecture, and formal ATF laser familiarization. Untrained...

  3. Laser satellite power systems

    SciTech Connect (OSTI)

    Walbridge, E.W.

    1980-01-01T23:59:59.000Z

    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  4. Laser-induced synthesis and decay of Tritium under exposure of solid targets in heavy water

    E-Print Network [OSTI]

    E. V. Barmina; P. G. Kuzmin; S. F. Timashev; G. A. Shafeev

    2013-06-03T23:59:59.000Z

    The processes of laser-assisted synthesis of Tritium nuclei and their laser-induced decay in cold plasma in the vicinity of solid targets (Au, Ti, Se, etc.) immersed into heavy water are experimentally realized at peak laser intensity of 10E10-10E13 Watts per square centimeter. Initial stages of Tritium synthesis and their laser-induced beta-decay are interpreted on the basis of non-elastic interaction of plasma electrons having kinetic energy of 5-10 eV with nuclei of Deuterium and Tritium, respectively.

  5. Fiber Lasers

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall ATours, Programs and EventsFiber Lasers NIF

  6. Laser Faraday

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sandLaser Decontamination ofFaraday

  7. Ultrafast Large Area Micropattern Generation in Non-absorbing Polymer Thin-Films by Pulsed Laser Diffraction

    E-Print Network [OSTI]

    Ankur Verma; Ashutosh Sharma; Giridhar U. Kulkarni

    2011-01-27T23:59:59.000Z

    We report an ultrafast, parallel and beyond-the-master micro-patterning technique for ultrathin (30 nm-400 nm) non-absorbing polymer films by diffraction of a laser light through a two dimensional periodic aperture. The redistribution of laser energy absorbed by the substrate causes self-organization of polymer thin-film in the form of wrinkle like surface relief structures caused by localized melting and freezing of the thin-film. Unlike the conventional laser ablation and laser writing processes, low laser fluence is employed to only passively swell the polymer as a pre-ablative process without the loss of material, and without absorption/reaction with the incident radiation. Self-organization in the thin polymer film aided by the diffraction pattern produces micro-structures made up of thin raised lines. These regular microstructures have far more complex morphologies than the mask geometry and very narrow line widths that can be an order of magnitude smaller than the openings in the mask. The microstructure morphology is easily modulated by changing the film thickness, aperture size and geometry and by changing the diffraction pattern, e.g., by changing the aperture-substrate distance.

  8. Evaluation of kinetic phosphorescence analysis for the determination of uranium

    SciTech Connect (OSTI)

    Croatto, P.V.; Frank, I.W.; Johnson, K.D.; Mason, P.B.; Smith, M.M.

    1997-12-01T23:59:59.000Z

    In the past, New Brunswick Laboratory (NBL) has used a fluorometric method for the determination of sub-microgram quantities of uranium. In its continuing effort to upgrade and improve measurement technology, NBL has evaluated the commercially-available KPA-11 kinetic phosphorescence analyzer (Chemchek, Richland, WA). The Chemchek KPA-11 is a bench-top instrument which performs single-measurement, quench-corrected analyses for trace uranium. It incorporates patented kinetic phosphorimetry techniques to measure and analyze sample phosphorescence as a function of time. With laser excitation and time-corrected photon counting, the KPA-11 has a lower detection limit than conventional fluorometric methods. Operated with a personal computer, the state-of-the-art KPA-11 offers extensive time resolution and phosphorescence lifetime capabilities for additional specificity. Interferences are thereby avoided while obtaining precise measurements. Routine analyses can be easily and effectively accomplished, with the accuracy and precision equivalent to the pulsed-laser fluorometric method presently performed at NBL, without the need for internal standards. Applications of kinetic phosphorimetry at NBL include the measurement of trace level uranium in retention tank, waste samples, and low-level samples. It has also been used to support other experimental activities at NBL by the measuring of nanogram amounts of uranium contamination (in blanks) in isotopic sample preparations, and the determining of elution curves of different ion exchange resins used for uranium purification. In many cases, no pretreatment of samples was necessary except to fume them with nitric acid, and then to redissolve and dilute them to an appropriate concentration with 1 M HNO{sub 3} before measurement. Concentrations were determined on a mass basis ({micro}g U/g of solution), but no density corrections were needed since all the samples (including the samples used for calibration) were in the same density matrix (1 M HNO{sub 3}). A statistical evaluation of the determination of uranium using kinetic phosphorimetry is described in this report, along with a discussion of the method, and an evaluation of the use of plastic versus quartz cuvettes. Measurement with a precision of {+-} 3--4% relative standard deviation (RSD) and an accuracy of better than {+-} 2% relative difference (RD) are obtained in the 0.0006 to 5 {micro}g U/g-solution range. The instrument detection limit is 0.04 ppb (4 x 10{sup {minus}5} {micro}g U/g solution) using quartz cells, and 0.11 ppb (11 x 10{sup {minus}5} {micro}g U/g solution) using disposable methacrylate cuvettes.

  9. Comparing the use of mid-infrared versus far-infrared lasers for mitigating damage growth on fused silica

    SciTech Connect (OSTI)

    Yang, Steven T.; Matthews, Manyalibo J.; Elhadj, Selim; Cooke, Diane; Guss, Gabriel M.; Draggoo, Vaughn G.; Wegner, Paul J.

    2010-05-10T23:59:59.000Z

    Laser-induced growth of optical damage can limit component lifetime and, therefore, increase operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, we quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {mu}m) versus far-IR (10.6 {mu}m) lasers in mitigating damage growth on fused silica surfaces. The nonlinear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda}=4.6 {mu}m, while far-IR laser heating is well described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on IR radiometry, as well as subsurface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally ablative conditions. Based on our FOM, we show that, for cracks up to at least 500 {mu}m in depth, mitigation with a 4.6 {mu}m mid-IR laser is more efficient than mitigation with a 10.6 {mu}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {mu}m in depth.

  10. Quantifying the Improvements in Rapid Prototyping and Product Life Cycle Performance Created by Machining

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    to laser ablation and 3D printing for rapid prototypinglaser ablation, and 3D printing. 2.1 ExperimentalMachining, Laser ablation, 3D printing, Microfluidics, Value

  11. Nonstoichiometric material transfer in the pulsed laser deposition of LaAlO{sub 3}

    SciTech Connect (OSTI)

    Droubay, T. C.; Qiao, L.; Kaspar, T. C.; Engelhard, M. H.; Shutthanandan, V.; Chambers, S. A. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

    2010-09-20T23:59:59.000Z

    Inequivalent angular distributions have been found for La and Al in the ablation plume from LaAlO{sub 3} single crystal targets using a KrF laser during pulsed laser deposition. Angular distributions and stoichiometries in the condensate were measured and reveal decidedly nonstoichiometric transfer from target to substrate over most of the angular range. Composition varied dramatically for plume angles parallel to the long axis of the laser spot with the on-axis position exhibiting a peak in the La/Al atom ratio at {approx}1.5. The distributions were more diffuse in the perpendicular direction. Stoichiometric LaAlO{sub 3} was found in the condensate only at an extreme off-axis position.

  12. Laser-assisted nanomaterial deposition, nanomanufacturing, in situ monitoring and associated apparatus

    DOE Patents [OSTI]

    Mao, Samuel S; Grigoropoulos, Costas P; Hwang, David J; Minor, Andrew M

    2013-11-12T23:59:59.000Z

    Laser-assisted apparatus and methods for performing nanoscale material processing, including nanodeposition of materials, can be controlled very precisely to yield both simple and complex structures with sizes less than 100 nm. Optical or thermal energy in the near field of a photon (laser) pulse is used to fabricate submicron and nanometer structures on a substrate. A wide variety of laser material processing techniques can be adapted for use including, subtractive (e.g., ablation, machining or chemical etching), additive (e.g., chemical vapor deposition, selective self-assembly), and modification (e.g., phase transformation, doping) processes. Additionally, the apparatus can be integrated into imaging instruments, such as SEM and TEM, to allow for real-time imaging of the material processing.

  13. High temperature ablation resistance of ZrNp reinforced W matrix composites

    E-Print Network [OSTI]

    Hong, Soon Hyung

    High temperature ablation resistance of ZrNp reinforced W matrix composites Malik Adeel Umer October 2013 Keywords: Metal-matrix composites (MMCs) Powder metallurgy Oxidation Scanning electron-based materials, a new class of composites was fabricated using particulate ZrN as reinforcement. The high

  14. Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

    SciTech Connect (OSTI)

    Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)] [University Hospital of Strasbourg (France)

    2013-12-15T23:59:59.000Z

    Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

  15. Bile Duct Disruption Following Radiofrequency Ablation: Successful Repair Using a Covered Stent

    SciTech Connect (OSTI)

    Thompson, Philip M.; Hare, Christopher M.B., E-mail: christopher.hare@uclh.org; Lees, William R. [Middlesex Hospital, Department of Radiology (United Kingdom)

    2004-08-15T23:59:59.000Z

    Persistent biliary leaks, whether iatrogenic or secondary to malignancy, often present a difficult management problem. Recent reports have suggested a role for covered metallic stents in this context. We describe the successful use of a covered stent to seal a persistent biliary leak following radiofrequency ablation of colorectal liver metastases.

  16. CT-Guided Radiofrequency Ablation in Patients with Hepatic Metastases from Breast Cancer

    SciTech Connect (OSTI)

    Jakobs, Tobias F., E-mail: tobias.jakobs@med.uni-muenchen.de; Hoffmann, Ralf-Thorsten; Schrader, Angelika [Ludwig-Maximilians-University of Munich, Department of Radiology (Germany); Stemmler, Hans Joachim [Ludwig-Maximilians-University of Munich, Department of Internal Medicine III (Germany); Trumm, Christoph [Ludwig-Maximilians-University of Munich, Department of Radiology (Germany); Lubienski, Andreas [University of Schleswig-Holstein, Department of Radiology (Germany); Murthy, Ravi [The University of Texas M. D. Anderson Cancer Center, Division of Diagnostic Imaging (United States); Helmberger, Thomas K. [Klinikum Bogenhausen, Department of Radiology (Germany); Reiser, Maximilian F. [Ludwig-Maximilians-University of Munich, Department of Radiology (Germany)

    2009-01-15T23:59:59.000Z

    The purpose of this study was to evaluate technical success, technique effectiveness, and survival following radiofrequency ablation for breast cancer liver metastases and to determine prognostic factors. Forty-three patients with 111 breast cancer liver metastases underwent CT-guided percutaneous radiofrequency (RF) ablation. Technical success and technique effectiveness was evaluated by performing serial CT scans. We assessed the prognostic value of hormone receptor status, overexpression of human epidermal growth factor receptor 2 (HER2), and presence of extrahepatic tumor spread. Survival rates were calculated using the Kaplan-Meier method. Technical success was achieved in 107 metastases (96%). Primary technique effectiveness was 96%. During follow-up local tumor progression was observed in 15 metastases, representing a secondary technique effectiveness of 86.5%. The overall time to progression to the liver was 10.5 months. The estimated overall median survival was 58.6 months. There was no significant difference in terms of survival probability with respect to hormone receptor status, HER2 overexpression, and presence of isolated bone metastases. Survival was significantly lower among patients with extrahepatic disease, with the exception of skeletal metastases. We conclude that CT-guided RF ablation of liver metastases from breast cancer can be performed with a high degree of technical success and technique effectiveness, providing promising survival rates in patients with no visceral extrahepatic disease. Solitary bone metastases did not negatively affect survival probability after RF ablation.

  17. Percutaneous Intraductal Radiofrequency Ablation is a Safe Treatment for Malignant Biliary Obstruction: Feasibility and Early Results

    SciTech Connect (OSTI)

    Mizandari, Malkhaz [Tbilisi State Medical University, Department of Radiology (Georgia); Pai, Madhava, E-mail: madhava.pai@imperial.ac.uk; Xi Feng [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom); Valek, Vlastimil; Tomas, Andrasina [University Hospital Brno Bohunice, Department of Radiology (Czech Republic); Quaretti, Pietro [IRCCS Policlinico San Matteo, Department of Radiology (Italy); Golfieri, Rita; Mosconi, Cristina [University of Bologna, Department of Radiology, Policlinico S. Orsola-Malpighi (Italy); Ao Guokun [The 309 Hospital of Chinese PLA, Department of Radiology (China); Kyriakides, Charis [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom); Dickinson, Robert [Imperial College London, Department of Bioengineering (United Kingdom); Nicholls, Joanna; Habib, Nagy, E-mail: nagy.habib@imperial.ac.uk [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom)

    2013-06-15T23:59:59.000Z

    Purpose. Previous clinical studies have shown the safety and efficacy of this novel radiofrequency ablation catheter when used for endoscopic palliative procedures. We report a retrospective study with the results of first in man percutaneous intraductal radiofrequency ablation in patients with malignant biliary obstruction. Methods. Thirty-nine patients with inoperable malignant biliary obstruction were included. These patients underwent intraductal biliary radiofrequency ablation of their malignant biliary strictures following external biliary decompression with an internal-external biliary drainage. Following ablation, they had a metal stent inserted. Results. Following this intervention, there were no 30-day mortality, hemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the 39 patients, 28 are alive and 10 patients are dead with a median survival of 89.5 (range 14-260) days and median stent patency of 84.5 (range 14-260) days. One patient was lost to follow-up. All but one patient had their stent patent at the time of last follow-up or death. One patient with stent blockage at 42 days postprocedure underwent percutaneous transhepatic drain insertion and restenting. Among the patients who are alive (n = 28) the median stent patency was 92 (range 14-260) days, whereas the patients who died (n = 10) had a median stent patency of 62.5 (range 38-210) days. Conclusions. In this group of patients, it appears that this new approach is feasible and safe. Efficacy remains to be proven in future, randomized, prospective studies.

  18. Stress (Tako-Tsubo) Cardiomyopathy Following Radiofrequency Ablation of a Liver Tumor: A Case Report

    SciTech Connect (OSTI)

    Joo, Ijin; Lee, Jeong Min, E-mail: jmsh@snu.ac.kr; Han, Joon Koo; Choi, Byung Ihn; Park, Eun-Ah [Seoul National University College of Medicine, Department of Radiology, and Institute of Radiation Medicine (Korea, Republic of)

    2011-02-15T23:59:59.000Z

    Stress cardiomyopathy is characterized by transient left ventricular dysfunction occurring in the absence of obstructive coronary disease. It is precipitated by acute emotional or physical stress. We present a case of stress cardiomyopathy which developed during hepatic radiofrequency ablation of hepatocellular carcinoma.

  19. ablated first-wall materials: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ablated first-wall materials First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Tungsten as first wall...

  20. Increasing Temporal Resolution in Greenland Ablation Estimation Using Passive and Active Microwave Data

    E-Print Network [OSTI]

    Long, David G.

    Increasing Temporal Resolution in Greenland Ablation Estimation Using Passive and Active Microwave of these measurements provides an increased understanding of the diurnal melt cycle over Greenland and estimation of the melt profile. I. INTRODUCTION Accurate estimation of the mass balance of the Greenland ice sheet

  1. RIS-M-2219 A numerical code for computing the ablated state of a

    E-Print Network [OSTI]

    RISÃ?-M-2219 PELREF A numerical code for computing the ablated state of a refuelling pellet C.4. Flow parameters at the sonic radius 11 2.5. The asymptotic solutions 13 3. COMPUTATIONAL CODE of the existing neutral shielding model , etc., it should be desirable to have such a computational code at our

  2. Photo-inducible cell ablation in Caenorhabditis elegans using the genetically encoded singlet

    E-Print Network [OSTI]

    Tsien, Roger Y.

    oxygen generating protein miniSOG Yingchuan B. Qia,1 , Emma J. Garrena , Xiaokun Shub,c , Roger Y. Tsienc-inducible and tissue-selective cell ablation using a genetically encoded photosensitizer, miniSOG (mini singlet oxygen generator). miniSOG is a newly engineered fluo- rescent protein of 106 amino acids that generates singlet

  3. ImageGuided Ex vivo Liver Ablation by Unfocused Ultrasound using Passive Cavitation Detection

    E-Print Network [OSTI]

    Mast, T. Douglas

    Image­Guided Ex vivo Liver Ablation by Unfocused Ultrasound using Passive Cavitation Detection echogenicity from image brightness. Passively detected acoustic emissions are used to quantify cavitation and cavitation. The latter two quantities can potentially be monitored noninvasively and used as a surrogate

  4. ablation-induced au condensates: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ablation-induced au condensates First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 JOURNAL DE PHYSIQUE...

  5. Sustained Growth of the Ex Vivo Ablation Zones' Critical Short Axis Using Gas-cooled Radiofrequency Applicators

    SciTech Connect (OSTI)

    Rempp, Hansjoerg, E-mail: hansjoerg.rempp@med.uni-tuebingen.de [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Scharpf, Marcus [Insitute of Pathology, Eberhard Karls University of Tuebingen, Department of General Pathology and Pathological Anatomy (Germany); Voigtlaender, Matthias [ERBE Elektromedizin GmbH (Germany); Schraml, Christina; Schmidt, Diethard [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Fend, Falko [Insitute of Pathology, Eberhard Karls University of Tuebingen, Department of General Pathology and Pathological Anatomy (Germany); Claussen, Claus D. [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Enderle, Markus D. [ERBE Elektromedizin GmbH (Germany); Pereira, Philippe L. [Klinik fuer Radiologie, Minimalinvasive Therapien und Nuklearmedizin (Germany); Clasen, Stephan [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany)

    2011-02-15T23:59:59.000Z

    Purpose: To evaluate the ablation zones created with a gas-cooled bipolar radiofrequency applicator performed on ex vivo bovine liver tissue. Materials and Methods: A total of 320 ablations with an internally gas-cooled bipolar radiofrequency applicator were performed on fresh ex vivo bovine liver tissue, varying the ablation time (5, 10, 15, and 20 min), power (20, 30, 40, and 50 W), and gas pressure of the CO{sub 2} used for cooling (585, 600, 615, 630, 645 psi), leading to a total of 80 different parameter combinations. Size and shape of the white coagulation zone were assessed. Results: The largest complete ablation zone was achieved after 20 min of implementing 50 W and 645 psi, resulting in a short axis of mean 46 {+-} 1 mm and a long axis of 56 {+-} 2 mm (mean {+-} standard deviation). Short-axis diameters increased between 5 and 20 min of ablation time at 585 psi (increase of the short axis was 45% at 30 W, 29% at 40 W, and 39% at 50 W). This increase was larger at 645 psi (113% at 30 W, 67% at 40 W, and 70% at 50 W). Macroscopic assessment and NADH (nicotinamide adenine dinucleotide) staining revealed incompletely ablated tissue along the needle track in 18 parameter combinations including low-power settings (20 and 30 W) and different cooling levels and ablation times. Conclusion: Gas-cooled radiofrequency applicators increase the short-axis diameter of coagulation in an ex vivo setting if appropriate parameters are selected.

  6. Longitudinal discharge laser baffles

    DOE Patents [OSTI]

    Warner, B.E.; Ault, E.R.

    1994-06-07T23:59:59.000Z

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam. 1 fig.

  7. Short wavelength laser

    DOE Patents [OSTI]

    Hagelstein, P.L.

    1984-06-25T23:59:59.000Z

    A short wavelength laser is provided that is driven by conventional-laser pulses. A multiplicity of panels, mounted on substrates, are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path. When the panels are illuminated by the conventional-laser pulses, single pass EUV or soft x-ray laser pulses are produced.

  8. Narrow gap laser welding

    DOE Patents [OSTI]

    Milewski, John O. (Santa Fe, NM); Sklar, Edward (Santa Fe, NM)

    1998-01-01T23:59:59.000Z

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables.

  9. Narrow gap laser welding

    DOE Patents [OSTI]

    Milewski, J.O.; Sklar, E.

    1998-06-02T23:59:59.000Z

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables. 34 figs.

  10. Creation of a Tumor-Mimic Model Using a Muscle Paste for Radiofrequency Ablation of the Lung

    SciTech Connect (OSTI)

    Kawai, T., E-mail: t.kawai@grape.med.tottori-u.ac.jp; Kaminou, T.; Sugiura, K.; Hashimoto, M.; Ohuchi, Y.; Adachi, A. [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine (Japan); Fujioka, S.; Ito, H. [Tottori University, Division of Organ Pathology, Department of Microbiology and Pathology, Faculty of Medicine (Japan); Nakamura, K. [Hakuai Hospital, Department of Radiology (Japan); Ogawa, T. [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine (Japan)

    2009-03-15T23:59:59.000Z

    The purpose of this study was to develop an easily created tumor-mimic model and evaluate its efficacy for radiofrequency ablation (RFA) of the lung. The bilateral lungs of eight living adult swine were used. A tumor-mimic model was made by percutaneous injection of 1.0 ml muscle paste through the bone biopsy needle into the lung. An RFA probe was then inserted into the tumor mimics immediately after tumor creation. Ablation time, tissue impedance, and temperature were recorded. The tumor mimics and their coagulated regions were evaluated microscopically and macroscopically. The muscle paste was easily injected into the lung parenchyma through the bone biopsy needle and well visualized under fluoroscopy. In 10 of 12 sites the tumor mimics were oval shaped, localized, and homogeneous on gross specimens. Ten tumor mimics were successfully ablated, and four locations were ablated in the normal lung parenchyma as controls. In the tumor and normal lung parenchyma, ablation times were 8.9 {+-} 3.5 and 4.4 {+-} 1.6 min, respectively; tissue impedances at the start of ablation were 100.6 {+-} 16.6 and 145.8 {+-} 26.8 {Omega}, respectively; and temperatures at the end of ablation were 66.0 {+-} 7.9 and 57.5 {+-} 7.6{sup o}C, respectively. The mean size of tumor mimics was 13.9 x 8.2 mm, and their coagulated area was 18.8 x 13.1 mm. In the lung parenchyma, the coagulated area was 15.3 x 12.0 mm. In conclusion, our tumor-mimic model using muscle paste can be easily and safely created and can be ablated using the ablation algorithm in the clinical setting.

  11. Nonlinear laser energy depletion in laser-plasma accelerators

    E-Print Network [OSTI]

    Shadwick, B.A.

    2009-01-01T23:59:59.000Z

    Nonlinear laser energydepletion in laser-plasma accelerators ? B. A. Shadwick,of intense, short-pulse lasers via excitation of plasma

  12. Usefulness of Guiding Needles for Radiofrequency Ablative Treatment of Liver Tumors

    SciTech Connect (OSTI)

    Baere, Thierry de, E-mail: debaere@igr.fr; Rehim, Mohamed Abdel; Teriitheau, Christophe; Deschamps, Frederic; Lapeyre, Mathieu; Dromain, Clarisse [Institut Gustave Roussy, Departement d'Imagerie Medicale (France); Boige, Valerie; Ducreux, Michel [Institut Gustave Roussy, Departement de medicine (France); Elias, Dominique [Institut Gustave Roussy, Departement de Chirurgie (France)

    2006-08-15T23:59:59.000Z

    Purpose. To evaluate the usefulness of a guiding needle for radiofrequency (RF) ablative treatment of liver tumors. Methods. Forty-two patients, 38-78 years old (57 {+-} 17), with 42 liver tumors (18 HCC, 24 colon cancer metastases) underwent RF ablation using a 14-gauge guiding needle with an external insulated sheath in which any 18-gauge or smaller needle can be placed, including a specially designed 3.5 cm LeVeen RF electrode. One guiding needle was used in 20 tumors to provide biopsy and RF treatment in a single puncture. Three to five guiding needles were loaded in 22 tumors measuring 35 to 64 mm in their largest diameter before starting RF treatment requiring multiple overlapping RF applications. Results. In the 20 RF treatments combined with biopsy, the biopsy was always contributive. Because of pre-positioning of the sheath, postbiopsy modifications (bleeding or air artifacts) did not hinder subsequent RF treatment. The 22 large tumors received 5 to 12 RF applications (mean = 6.8) through the three to five preloaded guiding needles. The RF ablation zones measured 46 to 94 mm (mean 55) in their largest dimension, with ablative margins in all cases. After 8 to 32 months (mean = 20), 14 of the 22 tumors are considered completely destroyed on computed tomography follow-up and one tumor seeding has been found. Conclusion. The Leveen CoAccess needle allows precise tumor targeting when treating large tumors requiring multiple RF applications. It allows biopsies combined with RF ablation through a single tract.

  13. Classical kinetic energy, quantum fluctuation terms and kinetic-energy functionals

    E-Print Network [OSTI]

    I. P. Hamilton; Ricardo A. Mosna; L. Delle Site

    2007-04-08T23:59:59.000Z

    We employ a recently formulated dequantization procedure to obtain an exact expression for the kinetic energy which is applicable to all kinetic-energy functionals. We express the kinetic energy of an N-electron system as the sum of an N-electron classical kinetic energy and an N-electron purely quantum kinetic energy arising from the quantum fluctuations that turn the classical momentum into the quantum momentum. This leads to an interesting analogy with Nelson's stochastic approach to quantum mechanics, which we use to conceptually clarify the physical nature of part of the kinetic-energy functional in terms of statistical fluctuations and in direct correspondence with Fisher Information Theory. We show that the N-electron purely quantum kinetic energy can be written as the sum of the (one-electron) Weizsacker term and an (N-1)-electron kinetic correlation term. We further show that the Weizsacker term results from local fluctuations while the kinetic correlation term results from the nonlocal fluctuations. For one-electron orbitals (where kinetic correlation is neglected) we obtain an exact (albeit impractical) expression for the noninteracting kinetic energy as the sum of the classical kinetic energy and the Weizsacker term. The classical kinetic energy is seen to be explicitly dependent on the electron phase and this has implications for the development of accurate orbital-free kinetic-energy functionals. Also, there is a direct connection between the classical kinetic energy and the angular momentum and, across a row of the periodic table, the classical kinetic energy component of the noninteracting kinetic energy generally increases as Z increases.

  14. Ultrahigh performance three-dimensional electromagnetic relativistic kinetic plasma simulation

    SciTech Connect (OSTI)

    Bowers, K. J.; Albright, B. J.; Yin, L.; Bergen, B.; Kwan, T. J. T. [Plasma Theory and Applications (X-1-PTA), Los Alamos National Laboratory, MS F699, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)

    2008-05-15T23:59:59.000Z

    The algorithms, implementation details, and applications of VPIC, a state-of-the-art first principles 3D electromagnetic relativistic kinetic particle-in-cell code, are discussed. Unlike most codes, VPIC is designed to minimize data motion, as, due to physical limitations (including the speed of light{exclamation_point}), moving data between and even within modern microprocessors is more time consuming than performing computations. As a result, VPIC has achieved unprecedented levels of performance. For example, VPIC can perform {approx}0.17 billion cold particles pushed and charge conserving accumulated per second per processor on IBM's Cell microprocessor--equivalent to sustaining Los Alamos's planned Roadrunner supercomputer at {approx}0.56 petaflop (quadrillion floating point operations per second). VPIC has enabled previously intractable simulations in numerous areas of plasma physics, including magnetic reconnection and laser plasma interactions; next generation supercomputers like Roadrunner will enable further advances.

  15. Chemical Dynamics, Molecular Energetics, and Kinetics at the Synchrotron

    SciTech Connect (OSTI)

    Leone, Stephen R.; Ahmed, Musahid; Wilson, Kevin R.

    2010-03-14T23:59:59.000Z

    Scientists at the Chemical Dynamics Beamline of the Advanced Light Source in Berkeley are continuously reinventing synchrotron investigations of physical chemistry and chemical physics with vacuum ultraviolet light. One of the unique aspects of a synchrotron for chemical physics research is the widely tunable vacuum ultraviolet light that permits threshold ionization of large molecules with minimal fragmentation. This provides novel opportunities to assess molecular energetics and reaction mechanisms, even beyond simple gas phase molecules. In this perspective, significant new directions utilizing the capabilities at the Chemical Dynamics Beamline are presented, along with an outlook for future synchrotron and free electron laser science in chemical dynamics. Among the established and emerging fields of investigations are cluster and biological molecule spectroscopy and structure, combustion flame chemistry mechanisms, radical kinetics and product isomer dynamics, aerosol heterogeneous chemistry, planetary and interstellar chemistry, and secondary neutral ion-beam desorption imaging of biological matter and materials chemistry.

  16. Eco Kinetics | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual SiteofEvaluating A Potential MicrohydroDistrictInformationEau ClaireEcoEco Kinetics Jump

  17. Amber Kinetics | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof Energy 2,AUDITCaliforniaWeifangwikiAgouraAlbatechFuels JumpKinetics Jump to:

  18. Three-Dimensional Laser Cooling

    E-Print Network [OSTI]

    Okamato, H.

    2008-01-01T23:59:59.000Z

    Three-Dimensional Laser Cooling H. Okamoto, A.M. Sessler,effective transverse laser cooling simultaneously withlongitudinal laser cooling, two possibilities are

  19. PALM - Laser Capture Microdissection | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    PALM - Laser Capture Microdissection PALM - Laser Capture Microdissection This Laser Capture Microdissection system is equipped with 100 x objective lens for enriching distinct...

  20. Kinetic bounding volume hierarchies for deformable objects

    E-Print Network [OSTI]

    Gabriel Zachmann; Tu Clausthal

    2006-01-01T23:59:59.000Z

    We present novel algorithms for updating bounding volume hierarchies of objects undergoing arbitrary deformations. Therefore, we introduce two new data structures, the kinetic AABB tree and the kinetic BoxTree. The event-based approach of the kinetic data structures framework enables us to show that our algorithms are optimal in the number of updates. Moreover, we show a lower bound for the total number of BV updates, which is independent of the number of frames. We used our kinetic bounding volume hierarchies for collision detection and performed a comparison with the classical bottomup update method. The results show that our algorithms perform up to ten times faster in practically relevant scenarios.

  1. Kinetics of the decomposition of tungsten hexacarbonyl

    SciTech Connect (OSTI)

    Podoprigora, V.I.; Baev, A.K.

    1987-07-20T23:59:59.000Z

    A differential-flow apparatus is devised for the study of the kinetics of the thermal decomposition of volatile metal carbonyls under quasi-stationary conditions. The applicability of the general kinetic approach to the investigation of the thermodecomposition of carbonyl compounds and of the analysis of the experimental data on the basis of specific thermodecomposition rates was proved. Well-founded kinetic characteristics were obtained for the first time for the thermodecomposition of tungsten carbonyl in the kinetic region and under quasi-stationary pyrolysis conditions.

  2. CLEERS Coordination & Development of Catalyst Process Kinetic...

    Broader source: Energy.gov (indexed) [DOE]

    2: ORNL Research on LNT Sulfation & Desulfation (8744, 8746) Jae-Soon Choi Oak Ridge National Laboratory CLEERS Coordination & Development of Catalyst Process Kinetic Data...

  3. The Fractional Kinetic Equation and Thermonuclear Functions

    E-Print Network [OSTI]

    H. J. Haubold; A. M. Mathai

    2000-01-16T23:59:59.000Z

    The paper discusses the solution of a simple kinetic equation of the type used for the computation of the change of the chemical composition in stars like the Sun. Starting from the standard form of the kinetic equation it is generalized to a fractional kinetic equation and its solutions in terms of H-functions are obtained. The role of thermonuclear functions, which are also represented in terms of G- and H-functions, in such a fractional kinetic equation is emphasized. Results contained in this paper are related to recent investigations of possible astrophysical solutions of the solar neutrino problem.

  4. CLEERS Coordination & Development of Catalyst Process Kinetic...

    Energy Savers [EERE]

    CLEERS Coordination & Development of Catalyst Process Kinetic Data - Pres. 1: Coordination of CLEERS Project; Pres. 2: ORNL Research on LNT Sulfation & Desulfation CLEERS...

  5. FIREBALL: Fusion Ignition Rocket Engine with Ballistic Ablative Lithium Liner

    SciTech Connect (OSTI)

    Martin, Adam K.; Eskridge, Richard H.; Lee, Michael H. [Propulsion Research Center, NASA Marshall Space Flight Center XD22, Huntsville, AL 35812 (United States); Fimognari, Peter J. [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2006-01-20T23:59:59.000Z

    Thermo-nuclear fusion may be the key to a high Isp, high specific power propulsion system. In a fusion system energy is liberated within, and imparted directly to, the propellant. In principle, this can overcome the performance limitations inherent in systems that require thermal power transfer across a material boundary, and/or multiple power conversion stages (NTR, NEP). A thermo-nuclear propulsion system, which attempts to overcome some of the problems inherent in the Orion concept, is described. A dense FRC plasmoid is accelerated to high velocity (in excess of 500 km/s) and is compressed into a detached liner (pulse unit). The kinetic energy of the FRC is converted into thermal and magnetic-field energy, igniting a fusion burn in the magnetically confined plasma. The fusion reaction serves as an ignition source for the liner, which is made out of detonable materials. The energy liberated in this process is converted to thrust by a pusher-plate, as in the classic Orion concept. However with this concept, the vehicle does not carry a magazine of autonomous pulse-units. By accelerating a second, heavier FRC, which acts as a piston, right behind the first one, the velocity required to initiate the fusion burn is greatly reduced.

  6. Simulations of laser imprint for Nova experiments and for ignition capsules. Revision 1

    SciTech Connect (OSTI)

    Weber, S.V.; Glendinning, S.G.; Kalantar, D.H.; Key, M.H.; Remington, B.A.; Rothenberg, J.L. [Lawrence Livermore National Lab., CA (United States); Wolfrum, E. [Rutherford Appleton Lab., Chilton (United Kingdom); Verdon, C.P.; Knauer, J.P. [Rochester Univ., NY (United States). Lab. for Laser Energetics

    1996-12-01T23:59:59.000Z

    In direct drive ICF, nonuniformities in laser illumination seed ripples at the ablation front in a process called ``imprint``. These nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser at LLNL examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, 1 {approx_equal} 10{sup 13} W/cm{sup 2} . The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National Ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of {approximately}10 nm RMS. Modulation growth was examined using the Haan [Phys. Rev. A {bold 39}, 5812 (1989)] model, with linear growth factors as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two-dimensional multimode growth were also performed. The capsule shell is predicted to remain intact, which gives a basis for believing that ignition can be achieved. 27 refs., 10 figs.

  7. Simulations of laser imprint for Nova experiments and for ignition capsules

    SciTech Connect (OSTI)

    Weber, S.V.; Glendinning, S.G.; Kalantar, D.H.; Key, M.H.; Remington, B.A.; Rothenberg, J.E.; Wolfrum, E.; Verdon, C.P.; Knauer, J.P.

    1996-11-08T23:59:59.000Z

    In direct drive ICF, nonuniformities in laser illumination seed ripples at the ablation front in a process called imprint. These non nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser at LLNL examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, I=10X13 W/cm3. The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National Ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of 10 nm RMS. Modulation growth was examined using the Haan model, with linear growth as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two- dimensional multimode growth were also performed. The capsule shell is predicted to remain intact, which gives a basis for believing that ignition can be achieved.

  8. Kinetics of actinide complexation reactions

    SciTech Connect (OSTI)

    Nash, K.L.; Sullivan, J.C.

    1997-09-01T23:59:59.000Z

    Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions.

  9. Combustion kinetics and reaction pathways

    SciTech Connect (OSTI)

    Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01T23:59:59.000Z

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  10. Laser studies of chemical reaction and collision processes

    SciTech Connect (OSTI)

    Flynn, G. [Columbia Univ., New York, NY (United States)

    1993-12-01T23:59:59.000Z

    This work has concentrated on several interrelated projects in the area of laser photochemistry and photophysics which impinge on a variety of questions in combustion chemistry and general chemical kinetics. Infrared diode laser probes of the quenching of molecules with {open_quotes}chemically significant{close_quotes} amounts of energy in which the energy transferred to the quencher has, for the first time, been separated into its vibrational, rotational, and translational components. Probes of quantum state distributions and velocity profiles for atomic fragments produced in photodissociation reactions have been explored for iodine chloride.

  11. Copper bromide vapour laser with a pulse repetition rate up to 700 kHz

    SciTech Connect (OSTI)

    Nekhoroshev, V O; Fedorov, V F; Evtushenko, Gennadii S; Torgaev, S N

    2012-10-31T23:59:59.000Z

    The results of the experimental study of a copper bromide vapour laser at high repetition rates of regular pump pulses are presented. A record-high pulse repetition rate of 700 kHz is attained for lasing at self-terminating transitions in copper atoms. To analyse the obtained results, use is made of the data of numerical modelling of the plasma kinetics in the phase of pumping and discharge afterglow. (lasers)

  12. Combinatorial pulsed laser deposition of doped yttrium iron garnet films on yttrium aluminium garnet

    SciTech Connect (OSTI)

    Sposito, A., E-mail: as11g10@orc.soton.ac.uk; Eason, R. W. [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom); Gregory, S. A.; Groot, P. A. J. de [Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2014-02-07T23:59:59.000Z

    We investigate the crystalline growth of yttrium iron garnet (YIG) films doped with bismuth (Bi) and cerium (Ce) by combinatorial pulsed laser deposition, co-ablating a YIG target and either a Bi{sub 2}O{sub 3} or a CeO{sub 2} target, for applications in microwave and optical communications. Substrate temperature is critical for crystalline growth of YIG with simultaneous inclusion of Bi in the garnet lattice, whereas Ce is not incorporated in the garnet structure, but forms a separate CeO{sub 2} phase.

  13. Development of a precise size-controllable pellet injector for the detailed studies of ablation phenamena and mechanism

    E-Print Network [OSTI]

    Ichizono, K; Nourgostar, S; Sato, K N; Group, Triam Exp.

    2004-01-01T23:59:59.000Z

    From the viewpoint of performance of nuclear fusion plasmas, pellet injection experiments have been actively carried out in many toroidal devices in the sense of controlling density profile, obtaining high density or improved confinement, and diagnostic purposes. In order to have a common measure of pellet ablation, the regression study has been performed as an international cooperation activity, obtaining "IPAD" (International Pellet Ablation Database) >. However, these are an empirical scaling, and the mechanism of pellet ablation still remains to be studied. According to the code calculations based on a typical pellet ablation model (e. g., so-called the neutral gas shielding model), it is understood that the penetration depth into plasma is always quite sensitive to the pellet size. If the pellet size is too large, the pellet passes through the plasma, and if it is too small, it is trapped at the plasma surface. Also, an effective or suitable range of the pellet size for a certain plasma is generally very...

  14. ADVANCES IN ENVIRONMENTAL REACTION KINETICS AND THERMODYNAMICS

    E-Print Network [OSTI]

    Sparks, Donald L.

    1262 ADVANCES IN ENVIRONMENTAL REACTION KINETICS AND THERMODYNAMICS: LONG-TERM FATE thermodynamic and kinetic data is available with regard to the formation of these mixed metal precipitate phases to six months from the initial addition of aqueous nickel. Additionally, we have determined thermodynamic

  15. Chemical kinetics and oil shale process design

    SciTech Connect (OSTI)

    Burnham, A.K.

    1993-07-01T23:59:59.000Z

    Oil shale processes are reviewed with the goal of showing how chemical kinetics influences the design and operation of different processes for different types of oil shale. Reaction kinetics are presented for organic pyrolysis, carbon combustion, carbonate decomposition, and sulfur and nitrogen reactions.

  16. Cost effective nanostructured copper substrates prepared with ultrafast laser pulses for explosives detection using surface enhanced Raman scattering

    SciTech Connect (OSTI)

    Hamad, Syed [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Podagatlapalli, G. Krishna; Soma, Venugopal Rao, E-mail: svrsp@uohyd.ernet.in, E-mail: soma-venu@yahoo.com [Advanced Center of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Mohiddon, Md. Ahamad [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)

    2014-06-30T23:59:59.000Z

    Ultrafast laser pulses induced surface nanostructures were fabricated on a copper (Cu) target through ablation in acetone, dichloromethane, acetonitrile, and chloroform. Surface morphological information accomplished from the field emission scanning electron microscopic data demonstrated the diversities of ablation mechanism in each case. Fabricated Cu substrates were utilized exultantly to investigate the surface plasmon (localized and propagating) mediated enhancements of different analytes using surface enhance Raman scattering (SERS) studies. Multiple utility of these substrates were efficiently demonstrated by collecting the SERS data of Rhodamine 6G molecule and two different secondary explosive molecules such as 5-amino-3-nitro-l,2,4-triazole and trinitrotoluene on different days which were weeks apart. We achieved significant enhancement factors of >10{sup 5} through an easily adoptable cleaning procedure.

  17. Kinetic advantage of controlled intermediate nuclear fusion

    SciTech Connect (OSTI)

    Guo Xiaoming [Physics and Computer Science Department, Wilfrid Laurier University, Waterloo, Ontario, N2L 3C5 (Canada)

    2012-09-26T23:59:59.000Z

    The dominated process of controlled fusion is to let nuclei gain enough kinetic energy to overcome Coulomb barrier. As a result, a fusion scheme can consider two factors in its design: to increase kinetic energy of nuclei and to alter the Coulomb barrier. Cold Fusion and Hot fusion are all one-factor schemes while Intermediate Fusion is a twofactors scheme. This made CINF kinetically superior. Cold Fusion reduces deuteron-deuteron distance, addressing Coulomb barrier, and Hot Fusion heat up plasma into extreme high temperature, addressing kinetic energy. Without enough kinetic energy made Cold Fusion skeptical. Extreme high temperature made Hot Fusion very difficult to engineer. Because CIFN addresses both factors, CIFN is a more promising technique to be industrialized.

  18. Preparation of germanium doped plasma polymerized coatings as ICF target ablators

    SciTech Connect (OSTI)

    Brusasco, R.M.; Saculla, M.D.; Cook, R.C.

    1994-10-05T23:59:59.000Z

    Targets for Inertial Confinement Fusion (ICF) experiments at the Lawrence Livermore National Laboratory (LLNL) utilize an organic (CH) ablator coating prepared by plasma polymerization. Some of these experiments require a mid-Z dopant in the ablator coating to modify the opacity of the shell. Bromine had been used in the past, but the surface finish of brominated CH degrades rapidly with time upon exposure to air. This paper describes the preparation and characterization of plasma polymer layers containing germanium as a dopant at concentrations of between 1.25 and 2.25 atom percent. The coatings are stable in air and have an rms surface roughness of 7--9 nm (modes 10--1,000) which is similar to that obtained with undoped coatings. High levels of dopant result in cracking of the inner mandrel during target assembly. Possible explanations for the observed cracking behavior will be discussed.

  19. Kinetic and mechanistic studies of free-radical reactions in combustion

    SciTech Connect (OSTI)

    Tully, F.P. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01T23:59:59.000Z

    Combustion is driven by energy-releasing chemical reactions. Free radicals that participate in chain reactions carry the combustion process from reactants to products. Research in chemical kinetics enables us to understand the microscopic mechanisms involved in individual chemical reactions as well as to determine the rates at which they proceed. Both types of information are required for an understanding of how flames burn, why engines knock, how to minimize the production of pollutants, and many other important questions in combustion. In this program the authors emphasize accurate measurements over wide temperature ranges of the rates at which ubiquitous free radicals react with stable molecules. The authors investigate a variety of OH, CN, and CH + stable molecule reactions important to fuel conversion, emphasizing application of the extraordinarily precise technique of laser photolysis/continuous-wave laser-induced fluorescence (LP/cwLIF). This precision enables kinetic measurements to serve as mechanistic probes. Since considerable effort is required to study each individual reaction, prudent selection is critical. Two factors encourage selection of a specific reaction: (1) the rates and mechanisms of the subject reaction are required input to a combustion model; and (2) the reaction is a chemical prototype which, upon characterization, will provide fundamental insight into chemical reactivity, facilitate estimation of kinetic parameters for similar reactions, and constrain and test the computational limits of reaction-rate theory. Most studies performed in this project satisfy both conditions.

  20. Laser preheat enhanced ignition

    DOE Patents [OSTI]

    Early, James W. (Los Alamos, NM)

    1999-01-01T23:59:59.000Z

    A method for enhancing fuel ignition performance by preheating the fuel with laser light at a wavelength that is absorbable by the fuel prior to ignition with a second laser is provided.